Note: Descriptions are shown in the official language in which they were submitted.
1~79868
-- 1 --
The present invention is concerned with an
insert element, more especial:Ly an insert element
for use with a rotor unit for a centrifugal analyser.
This application is a division of Canadian
Patent Application S.N. 390,835, filed ~ovember 24,
1981.
A rotor unit for a centrifugal analyser is
described having a rotor base connected with a drive
and a rotor head which, in operation, is connected
with the rotor base, the rotor head including chambers
for the reception of a sample liquid and, radially
outwardly from the associated sample chambers,
measuring chambers for the measurement of character-
istic parameters for the detection of components of
the sample, as well as liquid channels for connecting
the sample chambers with the measuring chambers.
The present invention is concerned with
insert elements for use with a centrifugal analyser
adapted for use with such a rotor unit.
Centrifugal analysers with a rotor unit of
the above-mentioned type have been conventional for
a number of years for the purposes of chemical analysis,
especially in clinical chemistry. They have circularly
symmetrically constructed rotor units with a plurality
., ~
~ .
~1~9868
- la -
of radial analysis channels. Usually, each analysis
channel has, from the inside towards the outside, a
trough-shaped reagent space, a sample space and a
measuring space which,` in the case of the known
devices, is constructed as an optical cuvette. The
rotor unit can be arranged in a rotor base and a
rotor head mounted non-rotatably on the rotor base.
The rotor base is usually constructed as a plate or
frame and
~179868
-- 2
securely attached to the axis of the rotor drive. The
term "rotor head" designates the remaining part of the
rotor unit which, in particular, includes the above-
mentioned analysis channels. In the case of more
recent centrifugal analysers, the rotor head is, as a
unit, exchangeable and is, in operation, non-rotatably
connected with the rotor base. The rotor head and the
rotor base can, in each case, be constructed in a large
variety of ways and can also differ substantially,
especially in the diameter of their outer boundary,
Thus, the rotor base can, for example, con5ist of only
a holder for the rotor head connected in one piece with
the rotor drive axis, which holder is, in operation,
completely superimposed by the rotor head.
In the case of the known devices, the rotor head
is, while stationary, filled with reagents and samples.
A device which can be used for this purpose is described
in Federal Republic of Germany ~atent Specification No.
2,626,810, which also describes the construction of a
typical rotor. As is to be seen from this German Patent
Specification, a complicated mechanical device is needed
for automatically filling the rotor.
After filling, the known rotor heads are placed
in the centrifugal analyser and connected with the rotor
base. The rotor is set in rapid rotation and, in the
case of some devices of this kind, alternating speeds
of rotation are used for mixing. Due to the centrifugal
1~79868
-- 3
acceleration during rotation of the rotor, the reagent
passes from its chamber into the sample chamber and
then the two together are passed ~nto the measuring
chamber, measurement there being carried out with the
rotor running. In the case of the known devices, the
measurement consists of a detèrmination of the optical
density of the liquid in the measuring chambers, which
are constructed as optical cuvettes. Thanks to modern
electronic evaluation devices, the absorption can be
measured in each cuvette at each rotation of the rotor.
In this way, the absorption in all cuvettes can be
observed almost continuously. In the case of a typical
rotational speed of 1000 rotations per minute, 1000
measurements are carried out per minute for each
cuvette. On the basis of this process, there is
obtained a precision of measurement which, in the case
of comparable analysis frequency, can scarcely be
achieved with conventional analysis devices, especially
in the case of so-called kinetic analysis determinations
in which the speed of the course of the reaction permits
conclusions to be made regarding the concentration of
a particular component.
The known centrifugal analysers have a number of
important advantages but also considerable disadvantages.
A summary of the most important requirements for an
optimum analysi~ device can be found in one of the
first public:ations concerning centrifugal analysers
~17~1~68
-- 4 --
(see Norman G. Anderson in "Analytical Biochemistry",
28, 545-562/1969) One of thes~ requirements is the
practically simultaneous measurement of several
reactions which, as described above, make possible a
bette,r monitoring of the individual courses of
reaction. Another requiremen~ i3 that the volumes of
the reagents and samples should be as small as possible.
This requirement is also substantially fulfilled by the
known centrifugal analysers but an improvement is still
desirable. Centrifugal analysers readily permit the
attachment of modern data evaluation systems for the
evaluation of the measurement results, i.e. not only
for the conversion of the absorption values into the
desired concentration values but also the statistical
evaluation of these concentrations in order to give
the physician information which is prepared as far as
possible.
Other requirements already mentioned in this
early article by Anderson are not fulfilled to a
desirable extent by the centrifugal analysers which
are at the moment conventional. The known devices
still require a large amount of attention from
personnel, they are not sufficiently simple to enable
them also to be used by untrained personnel and they
are not yet sufficiently flexible and variable in
order to be able to fulfil very different requirements,
especially in the operation of a clinical laboratory.
~79t36~3
-- 5
These deficiencies have, in the course of time,
given rise to a large number of developments of the
original concept, which have led to increasingly com-
plicated rotor constructions. Thus, these rotors were
expensive to produce but are still not able to fulfil
all the various requirements of the different analytical
determinations which are usual in clinical chemistry.
In particular, the known rotors can only be used
for carrying out one analytical determination for a
number of samples in one run of the rotor. As a rule,
however, in the clinical laboratory a series of differ-
ent analytical determinations must be carrie-d out on a
sample, for example blood from a patient, which, in
toto, are also called the profile. In the case of the
known analysers, this necessitates a considerable
amount of organisation. mus, the individually nec-
essary analytical determinations, communicated, for
example, by the physician to the clinical laboratory,
must be carried out gradually in separate rotor runnings
on one or more centrifugal analysers. Thereafter, the
separately determined data must ~e collated and passed
on to the physician. This complicated procedure not
only requires a considerable amount of organisation but
- is, unfortunately, not infrequently the cause of errors
of communication which can possibly result in false
therapeutic measures being carried out by the physician.
Thus, there is a need for centrifugal analysers which
,
98ti~
-- 6 --
can be adapted more variably and flexi~ly to various
tasks and which, in particular, can be used for pro-
file analyses or at least for several different
analytical determinations in one rotor running. This
is especially necessary for emergency analyses where,
under certain circumstances, several different
analytical determinations must be carried out in the
shortest possible time for one sample, i.e. for one
patient.
Another problem of clinical chemistry which is
not only typical for centrifugal analysers is that,
in the case of the known devices, obtaining the sample,
i.e. especially obtaining serum or plasma from blood,
and preparing the sample, i.e. especially diluting
serum or plasma to the concentrations necessary for
the analysis, take place in separate working steps
away from the analysis device. It is readily apparent
that, in this way, additional manual working steps and,
in particular, decanting steps are necessary. These
can, in turn, again result in mistakes being made or
can, for example, also result in contamination of the
samples.
There is herein described a rotor unit for a
centrifugal analyser of the initially described type
llt7~868
- 6a -
tllat, with avoidance of the disadvantages of known
centrifugal analysers, the simplest possible
operating is possible, together with a most flexible
and wide use as possible of the device.
The present invention seeks to provide
insert elements particularly for use in such a
rotor unit and in conjunction with an appropriately
constructed centrifugal analyser.
Thus according to the invention, there is
provided an insert element for use in a rotor unit
of a centrifugal analyser for the analytical deter-
mination of at least one component of a sample fluid
comprising:
a housing containing at least one sample
chamber for the reception of a sample liquid,
at least one measuring chamber for the
measurement of characteristic parameters f~r the
detection of components of the sample, while the
element rotates with the rotor unit,
a fluid connecting channel communicating
each sample chamber with an opposed measuring chamber,
- said housing having retaining means
adapted to cooperate with a rotor base of the rotor
unit such that said housing is adapted to be held
117~61~
-- 7 --
positionally stable on the rotor base when the
centrifugal analyser is in ope:ration, with the at
least one measuring chamber disposed radially out-
wardly of the at least one sample chamber, and
at least one analysis reagent disposed in
said channel between said sample chamber and its
opposed measuring chamber, such that in operation
a sample liquid in a sample chamber is brought into
contact with, and mixed with, the analysis reagent
in the channel, under the action of centrifugal
force before it reaches the opposed measuring chamber.
The rotor unit for a centrifugal analyser
may comprise a rotor base adapted to be connected
with a drive and a rotor head which, in operation,
is connected with the rotor base, the rotor head
including chambers for the reception of a s~mple liquid
and, radially outwardly from the sample chambers,
measuring chambers for the measurement of character-
is~ic parameters for the detection of components
of the sample, as well as channels for connecting
the sample chambers with the measuring chambers,
wherein the rotor head comprises a plurality of
insert elements of the invention, which are ex-
changeable and connectable with the rotor base at
~179868
- 7a -
different selected positions, the insert elements
being positionally stable when the centrifugal
analyser is in operation.
In particular each sample chamber com-
municates with a radially outward opposed measuring
chamber through a channel.
The rotor unit for a centrifugal analyser
may comrpise a rotor base adapted to be
- 8 - ~179~6~
connected with a drive and a rotor head which, in
operation, is connected with the rotor base, said
rotor head supporting a plurality of exchangeable
insert elements which are connectable with the rotor
base at different selectable positions, said insert
elements being positionally stable when the centrifugal
analyser is in operation, at least some of said
plurality comprising analysis elements, each analysis
element having at least one sample chamber for the
reception of a sample liquid and, radially outwardly
from the sample chamber, at least one measuring
chamber for the measurement of characteristic para-
meters for the detection of components of the sample,
and a fluid connecting channel, communicating each
sample chamber with a radially outward opposed
measuring chamber.
The insert elements may comprise different
insert elements including single analysis elements
and multiple analysis elements as well as elements
for obtaining or preparing a sample.
Each insert element contains devices for
carrying out part stages of analytical determination.
The external shape of the insert elements can differ
but they can, for example, also only differ in the
chemical composition of a part of their components.
It is import,ant that, by means of the present
invention,
1~98~;8
g
instead of the previously conventional, uniformly
constructed rotors, those are used, the rotor head of
which can receive a plurality~ of different insert
elements, a substantially increased variability thereby
being achieved. Whereas the known rotors, as mentioned
above, were only capable of fulfilling one particular
task, namely, as a rule, the determination of one
chemical component of a sample on a plurality of
samples in one rotor running (so-called "batch"
10 ` operation), in the case of the rotor unit according
to the present invention, each insert element can be
optimally adapted for a particular task. Due to the
possibility of connecting a plurality of diffarent
insert elements with the rotor base, for each rotor
running an individually adapted rotor can be assembled
which can then be used in a substantially more varied
manner. For example, in this manner, determinations
of several components of a sample (profile determin-
ation) are possible in one rotor running. Furthermore,
there are considerable handling simplifications, such
as are described hereinafter.
According to a preferred embodiment of the
present invention, the insert elements used can be
analysis elements of various constructions, such as
simple analysis elements which include devices for
determining one of the components of a sample and also
multiple analysis elements which have devices for
:1179868
--10--
simultaneously determining several components of one
or more samples. These insert elements can now be
adapted entirely to a particular analytical task.
Thus, in their construction, they can have different
analysis channels which are suppl~ed with liquid
reagents. However, they can also contain pre-packed
reagents, especially in solid form, which then, as
will be described hereinafter, are dissolved ~y the
diluted sample and mixed therewith. The term "insert
-element" or "analysis element" includes those of every
possible shape and size. Especially simple analysis
elements can be, for example, papers or fleeces impreg-
nated with reagents which can be exchangeably inserted
into the rotor head.
According to another preferred embodiment, the
insert elements according to the present invention
connectable with the rotor base include elements for
obtaining and preparing the samples. In this way, a
substantial disadvantage of the known centrifugal
analysers is also overcome. Thus, hitherto the sample
was, in each case, obtained and prepared separately
from the analysis device. In the case of blood
analysis, the blood must first, for example,-be centri-
fuged for obtaining serum or plasma and this then
appropriat~ly diluted before it can be introduced into
the sample chambers of a centrifugal analyser. For
transferring the samples into the rotor head outside
~179136~
'. --11--
of the apparatus, use was made, as mentioned herein-
~ before, of complicated apparatus or manual pipetting
was necessary. With the inslert elements according to
the present invention, hereinafter described in more
detail, for obtaining and/or preparing the sample, it
is now possible to carry out these important steps in
the centrifugal analysis device without manual trans-
fer procedures or other manual handling steps being
necessary. In this way, not only i5 the operating
simplified but the prevention of human errors also
increases the dependability.
The spatial measurements of the insert elements
are preferably supplemented in such a manner that
- - larger elements can be connected to the rotor base in
place of an inte~er multiple of the smallest
elements. This embodiment o~ the present invention
can also be expressed in such a manner that the
dimensions of the insert elements contain a raster
measure. A particular whole number fraction of the
rotor surface or of the rotor circumference determines
the base unit of the raster. The individual insert
elements are then so constructed that their spatial
requirement corresponds to a multiple of this raster
base unit. In this manner, the rotor unit according
to the present invention becomes especially variable
because comparatively large insert elements can now,
without waste of space, occupy the place of several
11791~613
-12-
smaller insert elements. The holders for the insert
- elements are, for the same reason, preferably arranged
periodically on the rotor base, insofar as t~ey each
lie on the same circumference, the periodicity length
of the holder arrangement thereby corresponding to the
base unit of the raster.
It is to be expressly pointed out that the
present invention is not limited to the case in which
the insert elements all have about the same radial
distance from the centre of the rotor. On the contrary,
for certain uses it can be highly desirable to arrange
the insert elements on different circumferences of the
rotor, for example in order thus to permit different
centrifugal accelerations to act upon the different
elements at a particular speed of rotation.
In this case, the holders for the insert elements also
have a different radial distance from the rotor centre
and thus lie on different circumferences~
A construction of the insert elements which,
viewed from the top of the rotor, has a circular sector
shape is especially preferred because various insert
elements thereby jointlessly abut one another and,
from the totality of the insert elements, there is
obtained an uninterrupted surface of the rotor head
when the rotor is completely loaded with insert
elements, although thi~ is not essential. The term
"circular sector shape" is here to be understood to
- 1~798~i8
-13-
mean that the bounding lines of the sectors, i.e.
viewed from the top of the rotor, ex-tend essentially
along the radii of the rotor circle. of course, the
present invention also inclucles solutions to the
problem in ~hich the outer edges differ from the
course of these radii in a definite manner which
repeats itself in the case of the different elements
so that the different insert elements, although they
do not have straight side surfaces, as a whole give
an uninterrupted loading of the rotor base. Such a
construction can be especially advantageous in order
to hold together the insert elements by a form-locking
construction of their side surfaces.
In conventional centrifugal analysis rotors, it
is known to construct the rotor head in two parts,
i.e. in a ring on the periphery of the rotor head,
which contains cuvettes for optical measurements and
an inner part, constructed, when viewed from above,
in circuiar form which fits the cuvette ring exactly
and, on its periphery, has through openings-which, in
the assembled state, are in alignment with and tightly
close the entry openings of the cuvettes. Upon rotation
of the rotor, the analysis liquid then passes from the
analysis channels in the circular inner part into the
cuvettes of the cuvette ring. Such a construction has
the advantage that the cuvette ring can be made from
high quality materials and made very precisely so that
~L79~68
the cuvettes have very good optical properties,
whereas the circular inner part can be ma~e comparat-
ively simply. Consequently, a preferred embodiment
of the present invention is also correspondingly con-
struc~ted. In this case, the cuvette ring is to be
regarded as being a part of the rotor head and is
- securely or exchangeably connected with the rotor
base.
All the measuring chambers preferably lie on
one circumference of the rotor head, i.e. they have
the same radial distance from the centre thereof, in
order that a single evaluation unit suffices for the
determination of the characteristic parameter which
must be measured for the detection of components of
the sample. As already mentioned, in the case of
known centrifugal analysers and preferably also in
the case of the device according to the present
invention, the optical absorption at one or more
wavelengths is determined as the characteristic
parameter for the detection of components of the
sample. However, the present invention is not limited
to such optical measurements. Precisely because of
the novel variability of the device according to the
present invention, it is also possible to carry out
completely d:ifferent determinations in a centrifugal
analyser, these including, for example, electrical
measurements in conjunction with electrochemical
~7~1~368
analysis processes of the most varied types. In
this case, the measuring chambers have electrodes,
the signals of which are passed in an appropriate
manner to the evaluation apparatus of the device,
for example via sliding contacts or without the use
of wires. In such cases, bult also in the case of
purely optical measurements, the measuring chambers
can also lie on different circumferences of the rotor
head.
The sample obtaining and/or sample preparing
elements have take-off points at which, by means of
appropriate devices of the apparatus, for example
canulae of automatic measuring devices or so-called
dispensers or dilutors, samples can be taken. These
take-off points preferably lie on an arc with the same
radius as the feed-in openings of the sample chambers
of the analysis element. It is thereby possible, for
~he transfer of the samples from the sample obtaining
or sample preparing elements to the analysis elements,
to use measuring devices which only move in a vertical
direction. The rotor is then brought into a position
appropriate for the removal or supply procedure by
means of a step-by-step switch device integrated into
the drive.
According to a further preferred embodiment, the
insert elements carry codings with regard to the sample
and/or the components of the sample to be determined
~3~7986~3
with the particular element. These codings can be
read by a reading means incorporated into the centri-
fugal analyser in order, in this way, to impart to
the device essential data for the evaluation and, at
the same time, to obtain a control for the correct
supplying of the rotor with the insert elements by
the operating personnel. Furthermore, the insert
elements preferably have markings for triggering the
measurement procedure. The insert elements have, of
course, in their position with regard to the rotor
base, certain tolerances, even though these may be
small in the case of precision construction of the
holder. Since, in general, the measurement procedure
must be triggered with regard to the position of the
insert element, it is especially advantageous when
the markings in question are on the insert element
and not, for example, on the rotor base.
The holding parts which, by form-locking
cooperation with the insert elements are preferably
used for their precise holding on the rotor base, are
preferably arranged in the region of the measuring
cells. Possible tolerances in the dimensions of the
insert elements thereby have especially little effect
with regard to the positioning of the measuring cells.
The present invention also provides insert
elements for use with the rotor unit according to the
present invention, which insert elements are especially
~7g~fi8
- 17 -
adapted for this purpose and make possible further
preferred embodiments of the rotor unit.
Preferred insert elements of this kind include
the reagents for carrying out analytical determin-
ations in a form which is storage-stable and which can
be transported with the insert elements. Such analysis
insert elements are especially advantageous for use as
"once oniy" elements, which can also be called dispos-
able elements. They are already provided by the
manufacturer with appropriate reagents for particular
analyses and are supplied to the user as a unit con-
taining the reagents. This obviates the handling of
individual and especially of liquid reagents, which
is a considerable simplification. Such disposable
elements can be made in a large number of versions,
- each version being suitable for one or more identical
or different analysis methods and includes the approp-
riate reagents, as well as appropriately shaped fluid
channels and other devices. For carrying out a
plurality of different analytical determinations, the
user has then only to select the appro~riate insert
element and to place it into the rotor unit.
An especially preferred insert element of the
invention for use in the rotor unit contains at least
one analysis reagent in dry form and
- 11798Çi8
-18-
a plurality of very small hollow spaces connected with
one another, which connect the sample chamber and
measuring chamber with one another. Such insert
elements are described in Canadian Patent Application
S~. 390,834, fil2d ~ovember ~4, 1981, Klose et al.
-Re~erence is m~a~ to the whole cont~nt of this
Canadian Patent Application. ~etails of the construction
of the insert elements described therein, which are
also important components of the present invention
and permit an especially advantageous use thereof,
are described in detail in this co-pending Canadian
Patent Application, reference to which is hereby made
without repeating the content of this Canadian Patent
Application.
Other preferred insert elements, namely sample
obtaining and/or preparing elements, can be used for
taking blood from a patient, for obtaining serum or
plasma by the action of centrifugal acceleration and
as sample vessels. These elements intended for blood
analysis save two additional vessels, namely, a syringe
for taking blood from a blood vessel of a patient and
a centrifuge tube for obtaining serum or plasma. At
the same time, transfer procedures from one vessel to
another are avoided. However, in con junction with the
present invention, it is especially important that the
obtaining and preparation of the sample, as already
mentioned hereinbefore, can, in the case of using such
1~L79868
--19--
insert elements, take place in the analysis apparatus
itself and that the sample is then, without manual
steps, transferred in a simple way from the sample
obtaining and/or preparing vessel in the analysis
apparatus itself into the analysis element.
For a thermostatic control of the sample, it is
also advantageous when these sample obtaining and/or
preparing elements are used in the rotor unit itself
according to the present invention. Thermostatic
control can be ensured by an appropriately regulated
heating of the rotor base and/or of a part of the rotor
head which is not exchangeable with the insert elements,
be it by a thermostated fluid flow or by direct
electrical heating or cooling. In order to achieve
a sufficiently precise thermostatic control of the
sample, this must be in thermal contact with the ~-
thermostatically controlled parts for a certain minimum
period of time. If the obtaining and preparation of
the sample take place away from the rotor, then, after
introducing the sample into the rotor head connected
to the rotor base, it is necessary to wait until the
time has expired which is necessary for this thermo-
stating. In contradistinction thereto, the sample in
the device described herein is already thermostated
during the centrifuging and possible further process
steps, for example during dilution of the s~mple.
Therefore, the analytical procedure can
1~798~
- 20 -
commence shortly after transferring the sample into
the analysis insert element. The saving of time
thereby resulting results in a greater analysis
capacity of the apparatus or in an increased exacti-
tude due to the improved thermostating.
The rotor unit described herein is pre-
ferably employed in a specially constructed centri-
fugal analyser which, in particular, includes
evaluation devices for the determination of several
10 different components of a sample in one rotor running.
As mentioned hereinbefore, the present invention makes
possible, in a simple manner, the determination of
several different components of a physiological liquid
in one rotor running. The determination consists of a
chemical reaction and the subsequent measurement of a
parameter, the value of which is characteristic for
the concentration of the component to be determined.
There is a number of known and proven specific
chemical reactions for various components of a sample,
especially in clinical chemistry, w~ich result in a
change of the same parameter characteristic for the
concentration, for example the optical absorption of
the solution at a particular wavelength. By way of
example, mention is made of the numerous reactions
which result in a change of the concentration relation-
ship of ~AD ,and ~ADH, the absorption of the solution
at 340 nm being characteristically influenced. Such
1~9~6~3
-21-
determinations, which result in a change of only one
characteristic parameter, can be evaluated with con-
ventional centrifugal analysers. However, in order
fully to utilise the versatility of the novel analysis
device according to the present invention, it is
advantageous when the centrifugal analyser employed
can evaluate several parameters in one rotor running.
In principle, these can also be of a different nature,
for example, the measurement of the optical absorption
and of the fluorescence and, under certain circumstances,
of electrical values. However, a centrifugal analyser
is especially preferred which can be used for the
determination of the optical absorption at several
different wavelengths in one rotor running, for which
purpose it has a poLychromic photometer. The term
"polychromic" is here not to be understood to mean
that the photometer operates with multicoloured light
but that it must be a photometer which can measure at
a number of different wavelengths, the change of the
wavelength being so coordinated with the course of
the measuring cuvettes of the rotor that the absorption
of each cuvette can be measured at any desired wave-
length.
Furthermore, a centrifugal analyser de-
scribed herein preferably also has a rotor drive
which not only, as in the case of the known apparatus,
is suitable for driving the rotor at a speed
~79~
-22-
of rotation appropriate for the mixing and measuring
procedures (usually about 1000 r.p.m.) but, in
addition, has a higher speed ~f rotation for centri-
fuging samples. Furthermore, the drive is preferably
to be capable of moving the rotor stepwise into certain
positions, which is of especial advàntage for the
preparation and distribution of the samples.
The present invention will now be described in
more detail, with reference to the accompanying
drawings, which illustrate several specific embodiments
and in which:
Fig.l is a perspective schematic illustration of a
rotor unit;
Fig.2 is a cross-section through a rotor unit
according to Fig. 1,
Fig.3 is a top view of a rotor unit from which,
in particular, the raster division can be seen;
Fig.4 is a schematic illustration of a view of a com-
bined sample obtaining and preparing element;
Fig.5 is a cross-section through an analysis insert
element for use with liquid reagents;
Fig.~ is a schematic illustration of a top view of a
preferred construction of an analysis channel;
and
Figs.7a and 7b are cross-sectional views through a
part of an analysis channel present in an
7~8~8
-~3-
analysis element according to the present
invention, with additional mixing devices.
Figs.l and 2 illustrate-a rotor unit, indicated
as a whole by 10, with a rotor base 12 and a rotor
head 14. The term "rotor head" includes all the con-
structional parts which can be connected with the rotor
base for the operation of the centrifugal analyser. In
particular, it includes the constructional-elements
necessary for the actual analysis. These include,
according to the present invention, in the first place
various analysis insert elements, for example simple
analysis elements 16 and multiple analysis elements,
such as the illustrated triple analysis element 18,
the sevenfold analysis element 20 and the elevenfold
analysis element 21.
Furthermore, a combined sample obtaining and
preparing element i~ indicated by 22. Not only on the
rotor base 12 but also on the insert elements 16, 18,
20, 21 and 22, there are provided mechanically readable
codings 24 and 26, respectively. The analysis elements
have inlet openings 28 for the introduction of a sample
into the sample chambers 29, cuvette windows 30 and
bores 32 which serve as trigger marks for the initiation
of the measuring procedure. In Fig.2`there is schemat-
ically illustrated a trigger signal emitter 33 which
contains a source of light and an optical receiver in
order to produce a trigger signal each time upon
~179~68
-24-
passing a trigger bore. The path of light for the
optical absorption measurement passes along the line
S-S in Fig.2 but, for the purpose of clarity, it is
not shown in detaii. It is of conventional construct-
ion, a polychromic photometer preferably being used.
In the case of the embocliment of the present
invention illustrated in the ~'igures, an optical
absorption measurement i9 employed as characteristic
parameter for the detection of components in a sample.
-10 This is the most conventional analysis process in
clinical chemistry but the present invention can also
be applied to other analytical principles in which, as
characteristic parameter, for example the fluorescence,
the luminescence, the reflection, the radioactivity or
electrical data of the reagent mixture are measured in
the measuring chamber in order to determine therefrom
the concentration of certain components of a sample,
for example of enzymes or substrates in a physiological
liquid.
In Fig.l, there can be seen two measuring
devices 34 and 36 which serve for measuring, diluting
and distributing the samples. There is preferably used
a sample-reagent measurer 34 which, in general, can
also be called a diluter, and a sample distributor 36
which, in general~ can be called a dispenser. Both of
them are arranged to be movable vertically in the
centrifugal analyser according to the present invention,
- 1~798~8
-25-
as is indicated by the double arrows 38 and 40.
The insert elements 16, 18, 20, 21 and 22 can
be connected by holding pins 42 to the rotor base 12,
which has corresponding holding slots 43 (see Fig.2).
The shapes of the holding slots 43 and of the holding
pins 42 are so adapted with regard to one another that
they fit into one another and ensure a position-stable
arrangement of the insert elements 16, 18, 20, 21 and
22. For fixing the insert elements, there is also
provided a central locking member 44 which, by means
of a thread 46, can be screwed on to the rotor base 12
and which lies upon seatings 48 of the insert elements
16, 18, 20, 21 and 22. The rotor base 12 is connected
via a driving axis 50 to a rotor drive for the centri-
fugal analyser. The quality of the mounting of the
driving axis and the weight of the rotor base are
important for a low vibration running of the rotor.
Furthermore, the weight distribution of the insert
eiements is preferably such that, even in the case of
different loading of the rotor, not too great an
imbalance results. Insofar as the rotor is not
completely loaded, it can be necessar~ to apply
appropriate weights to the rotor base in order to
avoid too great an imbalance.
Fig.3 shows a top view of a centrifugal analyser
according to the present invention which differs from
that illustrated in Figs.l and 2 in that it has place
~798~8
-26-
~or a larger number of insert elements. Fig.3 clearly
shows, in particular, the advantageous rastering
according to the present invention of the fixin~ means
and thus of the arrangement of the insert elements 16,
17, 19, 21 and 22, which can ~e changed as desired.
It can be seen that the circular surface of the rotor
base 12 is divided up into a plurality of whole seg-
ments B of the same size. In the illustrated embodi-
ment, these segments are sectors of a circle which
-10 are cut off on a radius corresponding to the inner
boundary 52 of the seating 48. Each sector corres-
ponds to a definite angular measurement of the circle
which is characterised as the basic unit of the raster
of the insert element arrangement and is indicated in
the Figure by reference G.
As can be seen from Fig.3, in the case of a
preferred embodiment, all the holding slots 43 for
the insert elements are arranged on the same circum-
ference ~. The arrangement is periodic with the
periodicity length a. It is important for the
present invention that the periodicity length a
corresponds to the basic unit G of the raster. It
is thereby possible to combine with this insert elements
of different sizes, for example elements 17, 19 and 21,
as desired and without waste of space on the various
places of the rotor base.
In contradistinction to Fig.l, Fig.3 shows
11~79~8
~;
-27-
analysis elements with five, eleven and seventeen
analysis channels, indicated by 17, 21 and 19,
respectively. The illustrated elevenfold analysis
element 21 corresponds in size to two base units of
the raster G and has two holding pins 42 on its under
side. The seventeenfold analysis element 19 has a
size corresponding to three raster base units G and
three holding pins 42. It can easily be seen that,
due to this construction according to the present
invention, an especially advantageous arrangement of
various insert elements on the rotor base is possible.
The illustrated embodim~nt is especially simple
in that the insert elements have, per raster unit of
their size, only one holder and are constructed as
simple sectors with straight side edges. Howèver,
the present invention includes a number of more com-
plicated constructions of the insert elements. Thus,
several holders per raster base unit bring about an
improved positioning of the elements. A construction
of the side edges 54 deviating from a straight line
can also improve the engagement from element to
element and thus the exactitude of the arrangement
thereof on the rotor base 12. Insert elements which
do not touch one another and are fixed spaced apart
on the rotor base can`be of advantage in certain cases.
The insert elements do not all have to be arranged with
the same radial distance from the centre of the rotor~
98~;8
-28-
In this case, not all of the holders are present on
the same circumference but, in this case, too, it is
advantageous when the periodicity length of the holders
present approximately on the same circumference corres-
pond tp the base unit of the particular associated
insert element raster. In all cases, it is important
that the spatial measurements of the insert elements
and the arrangement thereof are so adapted with regard
to one another that larger elements can be accommodated
in place of a number of the smallest elements. The
rastering according to the present invention can
thereby be used in a number of variations.
As can also be seen from the number of inlet
openings 28 and measurement chambers 30 of the analysis
elements in Fig.3, the multiple analysis elements 17,
19 and 21 each have a number of analysis channels which
is a multiple of six less one. In general, it can be
said that multiple analysis elements of the type accord-
ing to the present invention preferably have a number
of analysis channels which corresponds to a whole
number multiple of a base number less one, the base
number being the maximum number of analysis channels
of the smallest analysis element plus one. The des-
cribed preferred number of analysis channels of the
multiple analysis elements gives, in the case of the
above-described raster division, an optimal utilisation
of the elements but it should be borne in mind that the
~98~8
-29-
side edges of the insert elements have a certain
spatial requirement which, in each case, corresponds
approximately to the spatial requirement of one
analysis channel.
All the cuvette windows 30 are on a common
measurement circle which is s~own by a broken line
and indicated by M. In this way, a single photometer
suffices for all the measurements. According to the
present invention, the inlet openings 28 of the sample
chambers 29 in the analysis elements are also present
on the same circumfer~nce as the removal opening 56 of
the combined sample obtaining and preparing element 22.
This sample circle P is also illustrated by a broken
line.
On the left side of Fig.2 there can be seen the
combined sample obtaining and preparing element 22 in
cross-section. In Fig.4 it is again illustrated in
top view with the associated components. It preferably
has a cyiindrically-shaped inner chamber 58, the
circular cross-section of the cylinder lying in a plane
at right-angles to the plane of the paper in Fig.2~ On
the lower end of the insert element 22 on the left side
in Fig.2, there is a piston 60 in the
inner chamber 58. On the end opposite to the piston,
the inner chamber 58 is closed by an elastic stopper
62 made of rubber-elastic material which, according to
Fig.2, has a IU-shaped cross-section. On the same end,
986~3
-30-
there ~s a connecting part 64 for an injection needle
which can be connected with the insert element via a
connecting piece 68 cooperating with the connecting
part 64. The rear pointed encl 70 of the injection
needle 66 thereby penetrates into the closure stopper
62 of the insert element, an outwardly sealed off
fluid connection thereby being produced between the
hollow space of the needle 66 and the inner chamber
58 of the insert element 22.
In the assembled state, there is found upwardly,
in the region-of the closure stopper 62, the take-off
opening 56 of the combined sample obtaining and pre-
paring element 22. It opens in the middle chamber of
three dilution chambers 72, 74 and 76 (see Figs.3 and
4~. Similarly to the connection of the injection
needle 66, the take-off opening 56 is penetrated ~y a
needle-like canula of the corresponding diluter and
is again closed when the canula 78 of the diluter 34
is pulled out.
On the radial outer end of the insert element 22,
there can be connected a piston rod 80 which, passing
through bore 81, engages in a recess 82 of the piston
60 and can be positively connected therewith.
The combined samplè obtaining and preparing
element 22 according to the present invention is used
as follows:
~7~868
First it is provided at the intended places with
the injection needle 65 and the piston rod 80 and the
piston 60 is brought into the radially inner-lying
position (in Fig.2 on the rig~lt). The needle can then
be inserted into the blood vessel of a patient in order,
in conventional manner, to rernove blood, as with a
syringe, by pulling back the piston 60. The piston
is drawn back completely, the piston rod 80 and the
injection needle 66 are removed and the insert element
22 is placed into the analyser. After the rotor unit
10 has been loaded to the necessary extent for a
particular measurement, a centrifuging run is carried
out in the manner described hereinafter in more detail.
The solid components of the blood thereby collect on
the radially outer end of the insert element 22,
whereas radially more towards the interior of the
inner space 58 it is filled with serum or, if an
appropriate coagulation agent has been added, with
plasma. The further analysis steps are described in
more detailhereinafter in connection with the descrip-
tion of the total function of the apparatus.
Details of the construction of the analysis
elements are to be seen, in particular, in Figs. 2, 5,
6 and 7. In Fig. 2, the analysis channel of an es-
pecially preferred analysis element can be seen in
cross-section. This is indicated in the Figure with
16 as being a
31
~7986~
-32-
single analysis element. However, it is to be stressed
that the here-described const~lction of an analysis
channel, as well as a number of other constructions
adapted to a particular analytical purpose, can, if
desired, also be used in a multiple analysis element,
for example the elements 18, 20 and 21. For the
variability achieved by the present invention, it is
important that various analysis insert elements are
constructed in different ways, whereby not only the
io chemicals provided but also the physical construction
of the analysis channels can differ from one element
to another and, in the case of multiple analysis
elements, also within one element, depending upon the
purpose of the element, this depending upon the
analytical determinations to be carried out with the
element.
The analysis element illustrated in cross-section
in Fig.2 has a sample chamber 29, a measuring chamber
84 and a fluid channel 86 joining the two which, in
the present case, has, in the plane of the drawing of
Fig.2, a substantially rectangular cross-section and,
at rightangles to the plane of the drawing, only has
a comparatively small lumen. In a practical case, the
height of the fluid channel 86 is 6 mm. and the breadth
1 mm. The capacity of the sample space 29 is, in the
case of this embodiment, about 20 ~1. In the fluid
channel 86, t:here are fleece papers 88, 90 and 92
~IL179868
-33-
containing appropriate dry reagents for a particular
analysis. They have a plurality of small hollow
spaces connected with one another in which are present
the reagent and in which, at the same time, a distri-
bution and mixing up of the diluted sample takes in
or with the reagents, as is described in the above-
mentioned co-pending Canadian Pa~ent Application.
Radially in an out-
ward direction, the fluid channel has a connecting
channel 94 which opens into the measurement chamber
84. Radially inwardly, this is bounded by a barrier
96. The measurement chamber 84 is so dimensioned that
the sample-reagent mixture fills it, in the case of
centrifuging, to such an extent that the cuvette
window 30 is completely in the region of the fluid.
In principle, the analysis procedure takes place
in such a manner that the sample, i.e. the serum or
plasma in the necessary dilution, passes through the
~pening 28 and into the sample-chamber 29. The rotor
is then set into motion and the sample f~uid penetrates
into the fleece papers 88, 90, 92, dissolves t~e
reagents and, together with these, passes into the
measurement chamber. There, during the centrifuging,
in principle similarly to the case of the known centri-
fugal analysers, a determination is carried out of the
optical absorption in order to obtain therefrom the
desired concentration of a component of the sample.
1~79868
- 34 -
Further details are described in the above-mentioned
co-pending Canadian Patent Application and herein-
after in a specific Example.
High requirements are demanded of the materialused ~or making the insert elements and especially for
the analysis elements. It must be inert towards the
physiological fluids and reagents which come into con-
tact with it and yet must be capable of being worked
into the necessary shapes in an economic manner.
Furthermore, the cuvette windows 30 must be transparent
in the necessary spectral range. This is something of
a problem, especially in the case of the low wave-
lengths employed for analytical purposes (for examplè
340 nm.). Although, in the described embodiment, the
cuvette windows 30 are illustrated as elements inserted
into an injection moulded part, it can be desirable to
produce a larger part or even the whole of the upper
and lower sides of the analysis element from an approp-
riate transparent synthetic resin. Between these
transparent synthetic resin surfaces there is then
present, in a sandwich-like manner, a middle part which
laterally bounds the analysis channel with the sample
chamber 29 and the measuring chamber 84. The whole
insert element can, of course, also be made of trans-
parent material. Preferred optically transparent
~ materials include, for example, polymethyl methacrylate
and polystyrene.
11798~3
.
-35-
As already mentioned hereinbefore, the trigger
bores are preferably provided in the analysis elements
16 to 21 and not, for example, in the rotor base in
order to ensure a precise arrangement of their position
with regard to the cuvette openings 30. A further
advantage of this arrangement i5 that a measurement
procedure is actually only triggered off at rotor
positions at which it is also necessary. Thus, for
example, the sample obtaining and preparing element 22
has an uninterrupted shutter surface 35 and a single
analysis element 16 only one trigger mark whereas the
equally large triple analysis element 18 and the five-
fold analysis element 17 have three and five marks,
respectively. If the trigger marks were provided on
the rotor base and thus were not exchangeable with
the insert elements, the measurement procedures would
also be triggered off on those positions at which no
measurement is necessary. Especially in the case of
the use of a flashlamp for the photometer of the
centrifugal analyser, a considerable saving of energy
and increase of life result if no unnecessary measure-
ment ~rocedures and thus flashes are initiated by the
triggering.
It can also be seen from Fig.2 that, in the
previously described manner, the holders for the insert
elements, i.e. here the holding pins ~2, are present in
the region of the cuvette. Possible measurement
- ~7~868
-36-
deviations in the production of the insert elements
or due to thermal expansion act, due to this measure,
to a comparatively small extent on the distance of
the element holders 42, 43 to the cuvette windows 30.
As already mentioned, the analysis elements
preferably contain the reagents in a dry form already
pre-packed by the manufacturer because an especially
simple operating of the apparatus is thereby possible,
with a simultaneously high degree of flexibility.
However, for special reactions, it can also be
desirable to use liquid reagents, these preferably
being first introduced into the apparatus in the
analysis channel. Fig.5 shows an appropriate analysis
element 97 in radial cross-section through the middle
of its analysis channel. It can be seen that the
fluid channel 86 here forms an appropriate hollow
chamber for the reception of a reagent which is limited
by the barriers 100 and 101. The cover 102 of the
liquid analysis element 97 contains a filling opening
98 for the reagent. The sample chamber 29 ! fluid
channel 85, measuring chamber 84 and holding pin 42
are formed on the lower part 104 of the liquid
analysis element 97, which is welded to the covering
part 102.
For the operation of the liquid analysis element,
an appropriate reagent is introduced through the open-
ing 98 manually or with the help of a measuring device
1~'7~
-37-
not shown in Fig.l and arrangea on an appropriate
circumference of the centrifugal analyser. The
subsequent analysis procedure takes place analogously
to that in the known centrifugal analysers, the
advantage of the device according to the present
invention being that, as insert elements in a rotor
unit, there can be used thos~e filled with various
reagents and possibly differently shaped liquid
analysis elements 97.
Fig.6 shows a special embodiment of an analysis
channel of an analysis element 16, 17, 18, 19, 20 or
21. There is illustrated a cross-section roughly in
the middle of the height of the fleece paper contain-
ing reagents according to Fig.2, the cross-section
running parallel to the rotor surface. There can be
seen the sample chamber 29 and the fluid channel 86,
as well as the fleece papers 88, 90 and 92 containing
the reagents. The particular feature of the illustrated
embodiment is that, radially inwardly towards the
measurement chamber 84, two antechambers 106 are
connected which serve for a supplementary mixing of
the reagents dissolved out of the fleece papers 88,
90 and 92 with the sample solution.
In order to achieve this additional mixing
action, the centrifugal analyser is, in one mixing
run, accelerated and braked several times before the
measurement, the reaction mixture thereby alternatingly
~17~
-38-
penetrating at least partly into the antechambers 106
and then, when the acceleration in the peripheral
direction (tangential acceleration) stops, again
flowing back into the measuring chamber 84. A very
good mixing up is achieved by means of this procedure.
A mixing device based on the same principle can also
have a construction other than that here described,
all that is necessary being that the antechambers 106
lie radially inwardly from the measuring chamber 84
and, via appropriate small barriers 108, are in
connection therewith, the barriers having a height
such that they can be at least partly overcome by
the fluid in the case of accelerating or braking the
rotor and, on the other hand, do not hinder the flow-
bac~ of the fluid when there is no tangential
acceleration.
In a preferred embodiment of the present
invention, the walls 107 of the antechambers 106 are
provided with a curvature which, in the illustrated
cross-section, corresponds to an arc about a point
which, on the connecting line between the measuring
chamber 84 and the centre of the analysis rotor, lies
between these two points. Thi~ is indicated in Fig.6
by dotted lines, the middle point of the curvature
being indicated by K and the rotor centre by Z.
Figs.7a and 7b show other devices which can be
used for the additional mixing up of the reaction
791~68
-39-
mixture. These are static mixing devices which can
be arranged in the analysis elements in the fluid
channel before the measuriny chamber 84. The illus-
tration is a cross-section in the plane as in Figs.~
and 5. The direction of flcw of the reaction mixture
is indicated by arrows. The mixing action is, in the
case of Fig.7a, achieved by baffles 110 which divide
up the flow of fluid and again bring it together in
order thereby to achieve a mixing action. These
baffles can be cast in one piece on the appropriate
constructional parts of the analysis element. Anothèr
embodiment is illustrated in Fig.7b, in which case a
mesh structure 112 is introduced into the analysis
element and fixed at an appropriate part in the fluid
channel 86 and serves to divide up the reagent mixture
current, again to bring it together and thus to mix
it up.
In the following, there is explained the method
of operating the device according to the present
invention, the intermediate steps already previously
explained in detail here being only briefly mentioned.
For programming the whole device, it is prefer-
able to use a requirement card which can be completed
by the investigating physician. A coding for the
sample is contained therein in a mechanically readable
form, with which is associated the name of the patient.
This info~ation-is referred to as the sample identi-
1~ 7g~8
-40-
fication. By means of appropriate mechanically read-
able marking, the so-called requirement profile is
determined, i e. the physician stipulates which com-
ponents o~ the sample are to be analytically deter-
mine,d. The information ~s, in the following, called
the analysis identification.
With the help of the previously described
sample taking and preparing element, usable as a
syringe, a blood sample is taken from the patient.
The sample identification is, as coding 26, simult-
aneously applied to the insert element 22. This can
take place, for example, by transferring an approp-
riate adhesive label present on the requirement card
with a bar icoding on to the appropriate surface of
the sample obtaining and preparing element 22.
In the clinical laboratory with the device
according to the present invention, the requirement
cards of several patients are successively introduced
into an appropriate reading device of the apparatus.
In this way, the device obtains not only the sample
identification but also the analysis identification.
From these data, a calculator incorporated into the
device determines the necessary loading of the rotor
with the insert elements for the analyses to be carried
out. Corresponding directions for the rotor loading
are indicated on a picture screen device or by print
out. The :Loading can also take place fully automatic-
-41-
ally. The loading of the rotors is carried out
according to these instructions. This takes place,
in the case of the previously described embodiment
of the apparatus, in that, according to the directions,
sample obtaining and preparing elem~nt 22 and analysis
elements 16 to 21 are placed on the rotor base 12.
After the rotor base 12 is loàded, the central closure
44 is closed. The loading of the rotor takes place in
a manner which depends entirely upon the individual
case. If, for example, only one analysis is needed,
then, in addition to the sample obtaining and prepar-
ing element 22, there is merely placed on a single
analysis element 16. The next sample can thereafter
be placed on. In other cases, a particular, frequently
repeating profile is required, i.e. a series of
analyses important for a particular disease picture.
For other purposes, corresponding multiple analysis
elements 18, 20, 21 can be provided which, in their
individual analysis channels, contain various reagents
and in which the analysis channels can possibly also
be constructed with different shapes. Such profile
analysis elements make possible a particularly economic
determination of frequently recurring profiles. If,
in other cases, the same analysis is necessary for a
number of samples, other multiple analysis elements
can again be used which, in several analysis channels,
contain reagents for the same determination. In this
798~8
-42-
case, the appropriate sample obtaining and preparing
elements filled with the sam~les are successively
loaded on and subsequently the appropriate multiple
analysis element. Finally, compendious and special
anaLysis profiles can be fulfilled by a combination
of single and multiple analysis elements. It can be
seen that, by means of the device according tc the
present invention, a great flexibility is possible.
Handling is particularly simple because, especially
in the case of the use of prepacked dry reagents,
complicated manual steps are no longer necessary.
If a large sample throughput is required, it
can be desirable to load the rotor unit with the
- insert elements away from the centrifugal analyser.
For this purpose, it is desirable to provide inter-
mediate discs which are incorporated between the rotor
base and the insert elements in the apparatus and
thereby to load the insert elements away from the
apparatus in an appropriate manner. The unit com-
prising the intermediate disc and the insert elements
which, in this case, forms the rotor head, is then,
in its totality, placed in the centrifugal analyser.
The intermediate discs permit several rotor heads to
be loaded with insert elements and thus to prepare
them for the measurement while the centrifugal analyser
is, for exa!~ple, being used to carry out other
analyses.
1~L798~i8
-43-
After the rotor head, equipped with the insert
elements, has been placed in the apparatus and
connected to the rotor base, there follows the sample
obtaining run of the rotor in which, in the sample
obtaining and preparing elements, the sample, i.e.
serum or plasma, can be obtained in the above
described manner by centrifuging.
Thereafter follows the sample preparation which
includes, in particular, the appropriate diluting, the
stepwise functioning of the rotor drive according to
the present invention thereby being used. The rotor
is brought into a position in which the dilutor 34
stands precisely above the take-off opening of a
sample obtaining and preparing element 22. There-
after, the dilutor 34 moves down vertically, penetrates
the closure stopper 62, removes the sample by suction
and again moves upwardly in order to introduce various
diluted samples into the dilution chambers 72, 74 and
76 in the manner known for dilutors. By means of the
stepwise drive of the rotor, it is thereby, in each
case, brought into the correct position under the
dilutor 34. The precise positioning of the rotor is
simplified by the codings 24 provided on the rotor
base, which can be read off by a reading device present
on the apparatus and, in this manner, makes possible
a precise c:ontrol of the rotor.
The pre-diluting in the dilution chambers 72,
- 1~ 798~;B
-44-
74 and 76 (see Figs.3 and 4) has the advantage that
a comparatively large amount of sample can be diluted
relatively exactly. The amount of sample transferred
to the inlet openings 28 of the analysis elements is,
on ~he other hand, very small~ The dispenser 36 is
provided for sucking out an amount of diluted sample
sufficient for all the analyses to be carried out on
a particular dilution of a particular sample and for
dispensing it to the appropriate inlet openings of
the sample chambers. Of course, the functions of
the dilutor 34 and of the dispenser 36 can be ful-
filled by a single unit but the use of two separate
units is advantageous because a quicker loading of
the analysis elements is thus obtained.
During the sample diluting and dispensing, the
rotor moves stepwise back and forth, corresponding to
the coding 24, under the control of the central unit
of the centrifugal analyser. The dosing units 34 and
36 thereby only have to perform vertical movements.
Due to the thereby resulting mechanical simplicity
of the drive making this move~ent possible, an
economic construction and a great dependability of
the apparatus is achieved.
Before the following mixing and measuring, any
liquid analysis elements 97 present are provided with
reagents.
After completion of the sample dilution and
iL~79~8
.
-45-
dispensing, there follows the mixing and measuring
in which the centrifugal analyser is brought to the
speed of rotation necessary for the mixing and sub-
sequent measuring. During this running, the codings
26 on the insert elements 16, 18, 20, 21 and 22 are
- read by the apparatus and compared with the ~ed-in
sample identification and analysis identification.
Should a discrepancy be obsexved, error indications
are immediately given. In this way, an erroneous
analysis due to false loading of the rotor with the
insext elements is excluded with certainty. This
control can, of course, also take place after load-
ing or during the course of obtaining the sample.
For the various rotor runnings, in general
different speeds of rotation are necessary. Of
course, the necessary speeds of rotation depend upon
the diameter of the rotor used. The highest speeds
of rotation are, in normal cases, needed for centri-
fuging for obtaining serum or plasma samples. They
are of the order of several thousand rotations per
minute in the case of an effective rotor diameter
of about 25 cm.
The speed of rotation during the mixing and
measuring of the apparatus according to the present
invention must be adjusted to the particular analysis
insert elements employed. In the case of the use of
liquid analysis elements, the experience gained from
~17~8~8
- 4~ -
the use of conventional centriEugal analysers can
be used. Insofar as, use is made of the insert
elements according to the above-mentioned Canadian
Patent Application, the speeds of rotation in the
mlxlng and measuring runs of the apparatus are
also to be chosen accordiny to the instructions given
in such Canadian Patent Application. In one example o the
above mentioned Canadian Patent Application, use is made
of a comparatively small rotor of 33 mm. diameter in
which the measurement circle diameter is 28 mm. The
analysis channel is constructed according to the em-
bodiment illustrated in Fig. 6, the fluid channel 86
thereby having a breadth of 1 mm. and a height of 6 mm.
The fluid channel 86 contains fleece papers provided
with dry reagents, the radial distance of which from
the centre of the rotor is from about 4 to 10 mm.
Further details regarding the chemical composition
of the dry reagents and further constructional details
are given in the above-mentioned Canadian Patent
Application. The course of measurement consists, in
the case of the described measurements for example for
the determination of glucose described in the above-
mentioned Canadian Patent Application, of the following
steps:
1. Centrifuging at 2880 r.p.m. for 1 to 25 seconds.
The dilut:ed sample thereby penetrates into the
~ il7~8S8
-47-
first 1eece paper and dissolves out the reagent.
2. Centrifuging at 12000 r.p.m. for 5 seconds. The
solution is hereby driven out of the fleece into
the cuvette, only a minima]l amount of solution
remaining behind on the fleece.
3. A one second acceleration ~o 1200 r.p.m. and-
stopping of tha rotor for a further second. This
procedure is repeated 6 to 20 times, whereby, due
to the tangential acceleration, the solution is
driven into the antechambers 106 and a mixing effect
is thereby achieved.
4. ~ seconds centrifuging at 12000 r.p.m. for sediment-
ing impurities and for driving out air bubbles.
5. Measuring at 28~0 r.p.m.
If rotors of a different diameter are used or the
insert elements with the analysis reagents have a
different radial distance from the centre of the rotor,
corresponding speeds of rotation are to be used which
lead to the same values for the centrifugal acceleration.
Depending upon the dimensions and the analytical process
used, however, an empirical determination of the most
appropriate speeds of rotation is also necessary.
Since all insert elements which, in the case of
a particular rotor running, are connected with the rotor
are subjected to the same speed of rotation programme,
the analytical determinations simultaneously used must
be so coordinated with one another that they can be
,8
-48-
- carried out with the same speea of rotation programme.
As mentioned above, it is thereby possible also to
make use of the fact that the centrifugal acceleration
increases from the centre to the periphery of the
rotor. The radial arrange,ment, for example, of the
fleece papers or other reagent carriers within the
insert elements and/or the radial positioning of the
insert element itself are thus, for example, determin-
ing for the centrifugal forces to which the dilute
sample fluid or the reagent solution are subject in
such a reagent carrier.
Further measures for the adaptation to the
various analytical determinations to the given con-
ditions are described in the above-mentioned Canadian
Patent Application. By appropriate coordination of
the various measures mentioned, it is possible to
provide insert elements for a series of analytical
determinations which can be measured with the same
mixing and measuring run of the centrifugal analyser.
- 4g - 117~68
With further reference to Figure ~ the
fleece papers 88, 90 and 92 may be introduced into
rotor head 14 and insert elements 16, 17, 19 and 21
in a simple manner.
In particular as shown in Figure 2 insert
element 16 includes a lower part and a cover part,
which are identified as 104 and 102 respectively in
the similar insert element in Figure 5. The fluid
channel 86 is preferably of rectangul~ar cross-
section, the internal dimension at right angles tothe plane of the drawing in Figure 2 being relatively
small. When the cover part is removed, fleece papers
88, 90 and 92 may be easily inserted into the ~luid
channel 86 from above, after which the cover part may
be secured to the lower part, for example by gluing
or welding in the case of disposable insert elements
and by a mechanical connection whereby the cover part
can be removed, in the case of reusable insert elements.
As indicated above insert elements which
~0 may be used with or form a part of the.rotor unit
are more particularly described in the aforementioned
Canadian Patent Application.
The invention in the related co-pending
Canadian application is more especially concerned with
a process for carrying out analytical determinations
by mixing
1179~8
- 50 -
and incubating a sample solution with at least one
reagent solution and optical measurement of one para-
meter in the incubated reaction solution mixture,
mixing, incubating and measuring being carried out
during the action of a centrifugal force, wherein,
underthe influence of the centrifugal force, the sample
solution is brought together with a soluble dry reagent,
with at least partial dissolving thereof, and the
mixture or the solution is forced centrifugally through
a plurality of small hollow spaces, the centrifugal
force and the flow resistance of the small hollow
spaces being so adapted with regard to one another that
a complete dissolving of the removed portions and
mixing of the reaction components and possibly incuba-
tion takes place before the reaction solution passes
from the small hollow spaces into a measuring chamber
in which the measurement is carried out.
The process of the aforementioned copending
Canadian Patent application enables the previously com-
plicated construction of centrifugal analysis rotorsto be avoided and replaced by the simple constructed
rotor of the present invention, which is adapted for
the reception o exhangeable insert elements and which,
in spite of its simple mechanical construction, makes
all manipulations superfluous and merely requires the
introduction of the sample solution.
The plurality of small hollow spaces provided
in the insert element acts counter to the liquid flowing
~i7~8~8
- 51 -
outwardly into the measuring chamber under the influ-
ence of the centrifugal force with such a flow
resistance and, at the same time, brings about such
a complete mixing of the sample solution and of the
reagent to be dissolved in the sample solution that
special spatial constructions of mixing chambers, con-
necting channels and the like become superfluous and,
solely by the selection of the measurements of the
small hollow spaces, every desired flow velocity and
mixing intensity at a given centrifugal force can be
achieved.
The plurality of small hollow spaces necessary
herefor can be achieved in a very simple way by using
a mesh-shaped element, for example an interwoven mesh,
a paper strip, fleece or the like, or an open-celled
foamed material or a structured surface. The pores
and depressions contained therein form the small inter-
connected hollow spaces.
Therefore, the size of the hollow space corres-
ponds to the size of the open spaces in such mesh-
shaped elements and will normally not exceed about 2 mm.,
preferably 1 mm., the lower limit being determined by
the ability of the solution to pass through under the
action of the centrifugal force.
In~stead of a mesh-shaped element, use can
also be made, for example, of an open-celled foamed
material or of a structured surface which is covered
with a second surface which can be flat or also
- 52 _ 11 7 9 8 6 ~
structured. The structured surface can be not only a
roughened surface but also one provided with a plura-
lity of small pocket-like depressions. The connection
between the individual very small hollow spaces is, in
this case, obtained in that the second oppositely-lying
surface does not lie closely thereon but at a small
distance therefrom which is sufficient for the passage
of liquids under the influence of gravity. If two
structed surfaces thereby lie against one another, then
the structuring on both surfaces can be different so
that, depending upon the speed of rotation of the rotor,
differing effects can be brought about.
In the direction of flow of the liquid, i.e.
in the direction towards the measuring chamber, ele-
ments can also be provided with differing sizes of the
small hollow spaces and correspondingly different flow
resistances at a given centrifugal force. In this way,
it is possible, as desired, to increase or decrease the
rate of flow in the individual sections of the flow
path from the sample introduction point to the
measuring chamber.
It is possible employing such insert elements
to provide several different dry reagents with which
the sample solution is contacted under the influence of
the centrifugal force. Consequently, a multi-step
analytical determination can be carried out in which
different and successive reactions take place. It is
also possible spatially to separate different components
~ _ 53 ~ 7~
of a reagent which are not compatible with one another,
i.e. not only within the small hollow spaces but also
outside of them.
In a first embodiment employing such insert
elements, the sample solution, which can be used more or
less prediluted, is allowed to flow along a path pro-
vided with the very small hollow spaces in which the
average hollow space size ancl the average flow resis-
tance has the same value. This embodiment is especially
useful for one-step processes. If desired, a path with
increased flow resistance can follow as a braking path,
for example in order to increase the incubation time
until the reaction mixture enters the measuring chamber.
This is explained in more detail in the aforementioned
copending application.
In another embodiment employing such insert
elements the use of two incubation steps with the use
of two different reagents is possible. The sample fluid
is hereby first allowed to flow through a first element
having a plurality of very small interconnected hollow
spaces which contains a first dry reagent. Arranged
therebehind in the direction of flow there is a second
element with a plurality of very small interconnected
hollow spaces with a greater flow resistance than the
first element. This second element can be, for example,
a mesh-shaped body with denser packing of the fibres
than in the first element or can be a foamed material
with comparatively small pores. Consec~uently, this
_ 54 _ i 1 7198 ~ 8
second element has a greater flow resistance and brakes
the fluid so that the first reaction can take place
between the sample solution and the first reagent.
Beyond this second element is then arranged a third
element with a plurality of small interconnected hollow
spaces which, in turn, possessles a lower flow resistance
than the second element and which contains a second
reagent different from the first one. Thus, in the
case of this embodiment, the sample solution flows
through two incubation stages, between which is a
braking path. If desired, a further braking path can
be arranged to follow the third element.
A further preferred embodiment corresponds
to the above-described method with two incubation stages
and a braking for the fluid therebetween but, between
the second and the third element, an additional element
is provided in which a separation can be carried out.
In this additional, fourth element, the very small
hollow spaces either have a reactive surface or are so
constructed that they include a molecular sieve action.
In the case of a reactive surface, this either
has g~oups acting as an ion exchanger or contains
groups which manifest an affinity chromatography action
or contains enzymatically or immunologically active
bodies bound covalently or in some other manner. The
fixing of substances of the above-mentioned kind i.e.
of substances which are enzymatically active or
- 55 - 1 1 7 9 ~ ~ 8
immunologically active or are suitable for affinity
chromatography, on surfaces of solid bodies is well
known and does not need to be described here in more
detail. When the fourth element is, for example, a
mesh-shaped body which consists of cellulose or
polyamide fibres, then, for the activation of the
surface, use can be made, for example, of the processes
described in Federal Republic of Germany Patent
~:17~
- 56 -
Specifications Nos.2,708,018 and 2,438,436. The same
applies in the case of affinity chromatographically
active substances which are fixed on to the fibre
surfaces. In the case of surfaces with an ion exchange
function, the fourth element can consist of one of the
known ion exchange materials, for example can be based
upon sulphonated or amidated poly~tyrene resins,
celLuLose fibres or cross-linked dextran gels. The
fourth element with a chemically reactive surface can
also consist of a dense packing of very small granules
with reactive surfaces which can be made of substances
known for this purpose. Examples of such materials
include glass, metals, synthetic resin~, ceramic
granules and the like materials which are known to be
useful as carriers for chromatographically or biologic-
ally active substances.
As mentioned above, the dry reagent is preferably
arranged within the very small hollow spaces through
which the qample fluid flows. However, it is also
possible to place the reagent, for example in granul-
ated or tabletted form, before the very small hollow
spaces or in an interruption thereof. If, by approp-
riate choice of the centrifugal force and of the size
of the small hollow spaces, the rate of flow is
corre~pondingly small, the contact time between the
solid reagenl and the sample solution can be fixed
within wide limits so that sufficient time is available
~798~8
- 57 -
for complete dissolving of the reagent into the ~ample
solution. However, depending upon the nature of the
reagent used, it may suffice when only a part thereof
is dissolved out. In these cases, the reagent is
preferably used in an excess over the amount necessary
for the reaction with the sa~ple solution. The
reagent can also contain sparingly soluble or insoluble
particles which dissolve into the sample solution only
slowly or not at all. Such insoluble particles should
have a particle size which lies substantially below
the size of the small hollow spaces and their connect-
ing openings in order to ensure a satisfactory passage
through the small hollow spaces. However, it is also
possible, on a part of the path, so to construct the
very small hollow spaces that they exert a sieve
function on such insoluble particles.
~he described method of working with the arrange-
ment of elution and mixing paths, braking and incub-
ation paths and reactive surface paths can, of course,
also be supplemented by repetition of these process
sections, for example by combining the three above-
described methods of working in any desired way.
The measurement of the reaction results can be
carried out by the methods usual for this purpose,
for example, optically with the determination of the
reaction end point or by recordal of a kinetic reaction.
Conductivity measurements can also be carried out.
- 58 _ ~179~
The insert element can consist solely of a
mesh-shaped element which defines a plurality of very
small interconnected hollow spaces. ~xamples of such
mesh-shaped elements include interwoven meshes, fleeces,
papers, open-celled foamed materials, tightly packed
small bodies and the like. When the insert element
consists solely of such an element with very small inter-
connecting hollow spaces, then the analysis reagent is
contained in the hollow spaces in dry form. In the
simplest case, such an insert element can thus consist
only of a piece of fleece or paper impregnated with the
analysis reagent. Such an insert element can, for
example, be employed in such a manner that a centrifugal
analysis rotor body is provided which has a number of
circularly arranged sample supply chambers and a number
of measuring chambers associated therewith and arranged
radially outwards therefrom, which are connected to-
gether by radial slots, the insert element being tightly
and fittingly inserted into these slots, the sample
solution is introduced into the smaple supply chamber
and, after closure by a rotor cover plate or the-like,
a predetermined centrifugal force is produced, under
the influence of which the sample fluid is spun out-
wardly through the f~e~ce or paper. The fluid hereby
flows through the many very small interconnected hollow
spaces, dissolves the dry reagent, brings about a com-
plete mixing of the reaction components and an incuba-
taion due to the deflection of the direction of flow in
9~3~8
- 59 -
the passage from one very small hollow space to the next
which is necessary and finally passes into the measuring
chamber in which a measurement is carried out in
known manner.
However, in a further embodiment of the insert
element, this can also have a sample reception chamber
and/or a measuring chamber, in addition to the element
having the plurality of very small interconnecting
hollow spaces. Such an embodiment of the insert element
for example, consist of the element having the very
small hollow spaces in the form of a longitudinal body,
which is outwardly sealed off with a foil, which con-
sists, for example, of a synthetic resin, whereby, on at
least one narrow side of the longitudinal body, the foil
forms a loop which defines a measuring chamber and/or a
sample providing chamber. Such an insert element can,
for example, be produced in an extremely simple manner
by laying a rectangular paper or fleece strip impreg-
nated with the dry analysis reagent on to a synthetic
resin foil which projects slightly on both sides, for
example by 0.5 to 1 mm. On one end, the foil is folded
over and, on the other side of the strip laid in such a
manner that a small loop is formed on the folded over
end. By sealing the projecting edges of the foil, the
finished insert element is obtained. Instead of a foil,
correspondin~ly shaped bodies of synthetic resin or
similar shapable material can, of course, also be
employed.
:1179~
- 60 -
The insert element can contain several
usually different analysis reagents present spatially
separated from one another. As already mentioned, the
analysis reagents can be present within the very small
hollow spaces. For example, a definite amount of a
solution of the analysis reagent is applied to a point
of the element having the smal:l hollow spaces, for
example a fleece or paper strip, and dried, for example,
by lyophilisation or by some other method of drying.
Alternatively, the analysis reagent can also be present,
in the insert element according to the present inven-
tion, as a formed body, for example, in the form of
a granulate, in tabletted form or the like but then,
in general, is placed outside of the very small hollow
spaces.
The insert element can be made reactive on
at least a part of the surface of the small hollow
spaces. As already mentioned above, the mesh-shaped
body can hereby consist of fibres or filaments, on the
surface of which are fixed reactive substances, for
example enzymatically or immunologically reactive
substances. Reference is made to the above embodiment
in the scope of the explanation of the process.
Several elements or bodies, which have a
plurality of very small interconnected hollow spaces,
can be arranged side by side, or preferably, behind one
another forming the insert element, so that it is
~1798~
- 61 -
possible, by means of different sizes of the small
hollow spaces, to provide different flow resistances
and thus also rates of flow, ~ithout a variation of
the centrifugal force being necessary by change of the
speed of rotation. In the case of a mesh-shaped element,
the flow resistance is, for example, caused by the
thickness of the fibres and the nature of their connec-
tion. With decreasing fibre diameter, the average
diameter of the small hollow spaces becomes smaller and
the flow resistance increases correspondingly. Due to
~17~8~8
- 62 -
the nature of the connection of the individual fibres,
the size of the openings between the very small hollow
spaces is also influenced and, by utilisation of this
effect, the flow resistance can be adjusted to a
definite desired value. In this way, it is pos~ible,
within the insert element, to provide paths with a
greater and lesser flow resistance and thus to bring
about an acceleration or braking of the rate of flow
of the reaction solution.
10A preferred insert element is characterised in '
that, between the sample supplying chamber and the
measuring chamber, sections are arranged with differ-
ing average hollow space size~ which have differing
flow resistances for a throughflowing fluid.
A further preferred insert element is character-
ised by a first ~lement, which has a plurality of very
small interconnecting hollow spaces and contains a
~ first reagent, a second element, arranged therebehind
in the direction of flow, with a plurality of very
small interconnecting hollow spaces with a greater
flow resistance than the first element and a third
element, arranged therebehind in the direction of flow,
which has a plurality of very small interconnecting
hollow spaces which possess a lower flow resistance
than the hollow spaces of the second element and which
contains a second reagent.
- 63 _ ~7~&1~8
A further preferred insert element is
characterised in that, between the second and third
element, it has a further element with a plurality of
very small interconnecting hollow spaces which have a
reactive surface.
Such an insert element preferably also
contains elements which have enzymatically or
immunologically active substances bound to the surface
thereof.
A further preferred insert element contains
elements, the surfaces of which have reactive groups
with ion exchange properties.
The insert elements can also be present
bundled together to give larger segment-shaped units
so that an analysis profile can be determined in a
single worXing step since each individual element
permits the determination of another parameter of the
introduced sample. Such segment-shaped insert element
bundles can also be used for the simultaneous measure-
ment of a particular parameter in a plurality ofsamples. In this case, each insert element in the
insert element bundle contains its own sample intro-
duction chamber. It is clear that any desired
combinations between these embodiments are possible so
that many iclentical and/or different determinations
can be carried out simultaneously. The insertelements
can be made to be reusable but are preferably disposable.
- 64 ~ g~fi~
The reagents can be present in mixed form
or as individual components which, when the sample
fluid flows through, are successively dissolved and
mixed with one another. In this case, the various
mesh-shaped elements arranged in the insert element
can consist of individual paper strips each of which
contains a definite amount of reagent impregnated
therein. Such individual components of a carrier
containing an analysis reagent are described, for
example, in Federal Republic of Germany Patent Speci-
fication No. 2,852,994.
The aforementioned copending Canadian Patent
application describes a particular insert element
which comprises a fibre fleece which contains 40%
polyamide fibres and 40~/0 regenerated cellulose.
It has a take-up capacity for aqueous solutions of
about 500 ml/m in the case of a thickness of 0.5 mm
and a weight per unit surface area of 75 g,/m2
(VS 532* of the firm Binzer).
*Suppliers designation
