NMR measuring cell

The invention concerns a NMR measuring cell, in particular one for a flow-through probe head (1) and having at least a first inlet opening (10) to introduce a first injected or pumped reaction liquid into the measuring cell (1) and a second inlet opening (11) for introduction of a second injected or pumped reaction liquid into the measuring cell (1). The measuring cell (1)is subdivided by means of an at least partially movable wall (2) into at least a first chamber (17) which communicates with the first inlet opening and a second Chamber (19) which communicates with the second inlet opening (11). The at least partially movable wall (2) is configured and adapted in such a fashion that directed motion thereof leads to a mixing together of the first reaction liquid separately stored in the first chamber (17) with the second reaction liquid separately stored in the second chamber (19). In accordance with the invention a rapid and homogeneous mixing-together of the two reaction liquids is achieved in milliseconds.

BACKGROUND OF THE INVENTION 
The invention concerns a NMR measuring cell, in particular for a 
flow-through probe head, having a first inlet opening for injecting or 
pumping a first reaction liquid into the measuring cell and a second inlet 
opening for pumping or injecting a second reaction liquid into the 
measuring cell. 
This type of NMR measuring cell is known in the art through the publication 
JOURNAL OF MOLECULAR BIOLOGY, (1992), volume 224, no. 3, pages 733-859. 
An ESR measuring cell having the features of the above NMR measuring cell 
is known in the art through DD 109263. This conventional ESR measuring 
cell has means for disposing the reaction liquids near the measuring 
volume. Rotation of a cylindrical mixing chamber block causes introduction 
of the liquids into a mixing chamber via leads. The mixing chamber is 
located directly in front of the measuring volume. 
NMR flow-through measuring cells are, in particular, utilized in molecular 
biological proton folding applications. These applications examine, for 
example, polypeptide chains using NMR spectroscopy. The folding of these 
chains in combination with ribosomes is an important step for the transfer 
of genetic information in biological processes. The reaction mechanism and 
the precise motion dependence of these proteins is in principle up to this 
point in time, not fully studied and understood. The reaction mechanisms 
and the shape changes of these types of proteins which are important to 
biological reactions can be investigated in a time-dependent fashion using 
nuclear magnetic resonance spectroscopy. The reaction time constants are 
in the range of milliseconds to seconds. Consequently, it is important to 
effect the protein reactions being studied as quickly as possible, for 
example, in the range of milliseconds. 
Described in the journal NATURE STRUCTURAL BIOLOGY, volume 2, no. 10 
(1995), page 865 is a method in which the .alpha. lactobumin (BLA) is 
investigated in a series of one-dimensional nuclear magnetic resonance 
experiments. The reaction mechanism is triggered through the mixing of two 
reaction liquids. One reaction liquid contains the BLA. The BLA folding, 
which typically occurs with a time constant of 40 ms in the presence of 
Ca.sub.2+, is triggered by a rapid introduction of a second reaction 
liquid into the NMR measuring cell, the two reaction liquids being 
injected into the measuring cell. It has been experimentally determined 
that only after a mixing time of approximately 1 second are the two 
reaction liquids mixed together to an acceptable degree of homogeneity. 
The publication JOURNAL OF MOLECULAR BIOLOGY, volume 224, no. 3, page 
837-845 describes a similar method for investigation of enzyme folding. In 
this method the reaction liquids are brought together by means of a 
so-called Hamilton injector using a conventional T-jet mixer and 
introduced into a NMR measuring cell. The rapid mixing of the two reaction 
liquids triggers the reaction and the associated subsequent protein 
folding is investigated. The apparatus, including injection by means of 
the so-called Hamilton injectors, is thoroughly described in an article by 
Fersht, A. R. and Jakes, R. in Biochemistry, 14, (1975), pages 3350 to 
3356. The conventional method injects two reaction liquids into a 
measuring cell to bring the reaction liquids together and to mix them. 
The conventional methods have the disadvantage of requiring substantial 
mixing times before the two reaction liquids are mixed together in a 
sufficiently homogeneous manner. This can take up to 1 second or longer, 
wherein the investigation of reaction times for protein folding which lie 
significantly under one second, i.e. in the millisecond range, would be 
interesting. The conventional method leads to displacement and 
inhomgeneous thinning of the injected reaction liquid, particularly with 
large sample amounts. 
It is consequently the purpose of the present invention to present a NMR 
measuring cell which leads to a reliable rapid and homogeneous mixing of 
two reaction liquids within milliseconds. 
SUMMARY OF THE INVENTION 
This purpose is achieved in that the measuring cell is subdivided, by means 
of an at least partially movable wall, into at least a first chamber 
communicating with a first inlet opening and a second chamber 
communicating with a second inlet opening, wherein the at least partially 
movable wall is arranged and configured in such a fashion that a 
controlled movement of the at least partially movable wall leads to a 
mixing together of the first reaction liquid stored in the first chamber 
and the second reaction liquid stored in the second chamber. 
In this manner the purpose of the invention is completely achieved. The 
separate storage of the two reaction liquids in the measuring cell 
guarantees that sufficient time is available in order to introduce the two 
reaction liquids in a homogeneous, careful, and complete manner into the 
measuring cell. Only after the two reaction liquids have already been 
introduced into the measuring cell and initially separately stored are 
they brought into contact with another and thoroughly and quickly mixed 
together by means of rapid motion of the at least partially movable wall, 
to facilitate a rapid and homogeneous mixing within milliseconds. In 
contrast to the conventional method which introduces and mixes the 
reaction liquids by means of injection, the method in accordance with the 
invention facilitates measuring procedures which allow for large 
quantities of reaction liquids to be combined with each other in a rapid 
fashion. 
In an embodiment of the measuring cell in accordance with the invention the 
first chamber has a first outlet opening and the second chamber has a 
second outlet opening. This has the advantage that the two chambers can 
each be filled independently and separately from each other. 
It is advantageous when the measuring cell has a cylindrical shape. This 
has the advantage that the symmetry properties of the conventional NMR 
probe head configurations can be taken into consideration. 
In an embodiment of the measuring cell in accordance with the invention, 
the at least partially movable wall has mixing means, for example wings or 
diagonal openings. This has the advantage that the rapid motion of the at 
least partially movable wall simultaneously leads not only to removal of 
the separation between the two reaction liquids, but also facilitates 
their mixing, wherein a rapid homogeneous reaction mixture is established. 
It is advantageous when the at least partially movable wall comprises at 
least two components which are movable relative to each other and which 
interlockingly engage each other. This has the advantage that the liquids 
can initially be separately stored in the differing chambers defined by 
the mutually interlocking portions. The two reaction liquids can first 
come in contact and react with each other when the two mutually 
interlocking components are moved relative to each other. 
In an improvement in this embodiment the at least partially movable wall 
has a first component comprising wings and a second component having 
windows, wherein, in a first separating position of the wall, the wings 
interlockingly engage into associated windows in such a fashion that the 
first and second reaction liquids are stored separately and in a second 
mixing position of the wall, the wings open the windows in such a fashion 
that a mixing of the first and second reaction liquids takes place. This 
measure has the advantage that the dove-tailing of the mutually 
interlocking wings and windows initially facilitates complete and 
definitive separate storage of the reaction liquids. Subsequent to the 
time at which the liquids are filled into the appropriate chambers it is 
possible for a rapid motion of the wing component relative to the window 
component to not only cause openings between the first and second 
chambers, but the relative motion between the window and wing components 
also causes a mixing together of the two mutually reacting liquids. 
In an improvement of this embodiment, the two moving components rotate 
relative to each other. This has the advantage that the rotational motion 
facilitates a rapid relative motion between the two movable parts and a 
good mixing together of the two reaction liquids in a mechanically simple 
manner, wherein a good fitting-together of the two mutually interlocking 
components is also guaranteed. 
In an improvement in this embodiment one part of the at least partially 
movable wall is stationary within the measuring cell and the second 
component rotates about an axis disposed vertically in the center of the 
measuring cell. This measure has the advantage that one part of the 
measuring cell can be stationary so that only one moving part is 
necessary. The moving component is, for its part, rotationally borne in 
the measuring cell and rotates about a vertical axis in the measuring 
cell. In this manner, an advantageous cylindrical configuration of the 
measuring cell is given, wherein the rotating component rotates about the 
central axis of the cylinder-shaped measuring cell. The rotating component 
maintains its geometrical configuration during rotation relative to the 
side walls of the measuring cell, while nevertheless moving relative to 
the stationary installed component of the at least partially movable wall. 
It is advantageous when the stationary component has windows and the 
movable component wings. This has the advantage that wings fashioned on 
the movable component move in a propeller-like fashion through the 
reaction liquid by means of the motion of the movable wall relative to the 
stationary wall and cause an homogeneous and rapid mixture of the two 
reaction liquids. 
In an advantageous embodiment the wall separates four, in general 2n, 
chambers, wherein n is a whole number and each chamber has an inlet 
opening. This has, for example when mixing two reaction liquids, the 
advantage that the two oppositely lying chambers can be filled with the 
same reaction component and the intervening chambers can be filled with 
the reaction partner. In this fashion the reaction area which is available 
to the two reaction liquids is increased which, for its part, leads to a 
more rapid and homogeneous mixing of the two reaction liquids. 
In an advantageous improvement of this embodiment the NMR measuring cell is 
characterized in that the at least partially movable wall has a 
cross-shaped cross section. 
This has the advantage that the wall can be easily disposed in a 
cylinder-shaped measuring cell. When, for example, one component of the 
movable wall rotates relative to the other component this cylindrical 
symmetry of the measuring cell allows the cross-shaped configuration to 
guarantee a sealing separation between the reaction liquids before 
triggering the reaction. However, the e.g. rotational motion of the 
rotating part does not change the geometrical orientation of the rotating 
part with respect to the cylindrically shaped measuring cell, wherein the 
rotational motion facilitates both separation by means of the 
interlockingly engaging stationary and movable components as well as 
mixing. 
In another embodiment the wall and/or the measuring cell are configured in 
such a fashion that the wall is at least partially retractable from the 
measuring cell to facilitate the mixing of two reaction liquids. This 
measure has the advantage that the two reaction liquids can initially be 
introduced and separately stored in the measuring cell in a relatively 
simple manner. The two reaction liquids are then subsequently rapidly 
brought into mutual reaction when the movable wall is at least partially 
retracted out of the cell. 
In an improvement of this embodiment, a seal is provided for between the 
wall and measuring cell, to store the first and second reaction liquids in 
a sealing fashion in the first and second chambers respectively. This has 
the advantage that the two chambers can initially be sealed-off from each 
other, wherein the two reaction liquids can be introduced and stored 
separately in the measuring cell. When preparations for the measurement 
are sufficiently completed and after the reaction liquids have been 
brought into the measuring cell, the reaction can be induced through at 
least partial retraction of the movable wall from the measuring cell. 
In an improvement of this embodiment the at least partially movable wall 
has mixing means, for example, wings or diagonal openings. This measure 
has the advantage that retraction of the at least partially movable wall 
simultaneously leads to a mixing of the two reaction liquids, wherein the 
pulling-out and the motion which is thereby caused simultaneously serves 
as motional energy for mixing. 
It is advantageous when the mixing of the two reaction liquids is caused by 
a vertical motion of the wall parallel to the longitudinal axis of the 
measuring cell. This has the advantage that a cylindrical measuring cell 
can also be easily configured in such a fashion that the two chambers are 
initially kept separate from each other and are subsequently brought into 
reaction contact with another. 
In an improvement of this embodiment, the wall can be pulled through an 
upper end of the measuring cell out of the measuring cell. This has the 
advantage that a relatively compact configuration is guaranteed which is 
mechanically simple to manufacture. 
It is advantageous within the context of this embodiment when the wall 
includes a pipe-shaped component, wherein the first chamber of the 
separated measuring cell is located within the pipe-shaped component and 
the second chamber is formed between the outer wall of the measuring cell 
and the outer surface of the pipe-shaped component. The high symmetry of 
this configuration is particularly advantageous for precise NMR 
measurements. The cylindrical symmetry of the pipe-shaped component 
additionally facilitates a simple removal of the pipe-shaped component, 
for example through the upper end of the measuring cell, wherein a compact 
configuration leading to a rapid and reliable mixing is guaranteed. 
In a further improvement of this embodiment the pipe-shaped component is 
configured as a hollow cylinder and the measuring cell has a ring-shaped 
gap on its upper end, wherein mixing Of the two reaction liquids is 
effected by the retraction of the hollow cylinder through the ring-shaped 
gap. This has the advantage that a cylindrical symmetry can be utilized 
and a ring-shaped gap can be provided with, for example, an O-ring seal. 
In this manner the two reaction liquids are initially separately stored in 
the measuring cell. Following preparation of the reaction liquid and the 
measurement the cylinder-shaped part of the separation wall is pulled 
through the ring-shaped gap formed in the upper portion of the measuring 
cell, wherein the two reaction liquids react with each other in a rapid 
manner. 
It is advantageous when the wall comprises a radially extended base on one 
end thereof to strengthen mixing of the two reaction liquids. This has the 
advantage that the retraction of the movable wall simultaneously leads to 
a good mixing together of the reaction liquids. 
In an advantageous improvement of this embodiment, the base has diagonal 
bores or wings. This has the advantage that additional mixing mechanisms 
are provided for on the base which lead to a better and more rapid mixing 
of the two reaction liquids. 
In an advantageous method in accordance with the invention for the rapid 
mixing of at least two reaction liquids in the measuring cell of a NMR 
spectrometer, an elution corresponding to a chromotography signal peak (LC 
peak) is separated from a column of a liquid chromotography apparatus (LC 
column) and introduced on-line as a reaction liquid into a chamber of the 
measuring cell. This has the advantage that the NMR measuring cell in 
accordance with the invention is also suitable for coupled LC-NMR 
measurements. The on-line coupling of LC and NMR is e.g. discussed in DE 
41 04 075 C1. 
Further advantages of the invention can be derived from the description and 
the drawing. The above mentioned features and those to be described 
further below can be utilized in accordance with the invention 
individually or collectively in arbitrary combination. The embodiments 
shown and described are not to be considered as exhaustive enumeration 
rather have exemplary character only for illustration of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The figures are partially shown in a very schematic fashion in order to 
emphasize the essential features of the invention. In these 
representations the dimensions are only exemplary and are not necessarily 
to be taken to scale. 
FIG. 1 shows a measuring cell 1 which, for example, is configured for NMR 
flow-through measurements, comprising an upper component 7, a lower 
component 8 as well as a side wall 14 connecting the upper and lower 
components. A mixing cross configuration 2 is located within the 
cylindrically shaped measuring cell 1 and is coaxially disposed within the 
measuring cell 1. This vertical cut through the measuring cell 1 in 
accordance with FIG. 1 illustrates two components of the mixing cross 
configuration 2. The first component 3 has window openings which 
interlockingly engage wings 15 of a wing component 4. In the embodiment in 
accordance with FIG. 1, the window component 3 is stationary within the 
measuring cell 1 and the wing component 4 comprises a central axis 6 which 
is disposed coaxially with respect to the cylindrical side wall 14 of the 
measuring cell 1. The window component 3 has a central bore 5 through 
which the axis 6 of the wing component 4 penetrates. The axis 6 is borne 
in a pivotable fashion in a rotation mounting 9 and is seated in a guide 
means 23 of the upper component 7. 
The lower component 8 of the measuring cell 1 has a plurality of inlet 
openings, for example, a first inlet opening 10 as well as a third inlet 
opening 11. A first outlet opening 12 and a third outlet opening 13 are 
located in the upper component 7 of the measuring cell 1 and are 
associated with these inlet openings 10, 11 in the lower component 8 of 
the measuring cell 1. As described further below, the first inlet opening 
10 communicates with the first outlet opening 12 and the third inlet 
opening 10 communicates with the third outlet opening 13 in that state of 
the movable wall in which the reaction liquids are separated. 
FIG. 2 shows a perspective view of the component 4 of the at least 
partially movable wall having wings 15 in accordance with the mixing cross 
configuration 2 of FIG. 1. The wing component 4 has a central axis 6 which 
is mounted in a rotating fashion on a rotation mounting 9. The wing 
component 4 has a plurality of cross-shaped wings 15 each of which is 
securely mounted to the rotational axis 6. The wings 15 are disposed 
symmetrically about the rotational axis 6 in the embodiment of FIG. 2. 
Rotation of the rotational axis 6 in the direction of arrow 24 causes the 
wings 15, which are securely mounted to the rotational axis 6, to likewise 
be brought into rotational motion. 
A perspective view of the window component 3 is represented in FIG. 3. The 
window component 3 has a central bore 5 through which the rotational axis 
6 of the wing component 4 penetrates. The windows 16 formed in the window 
component 3 are dimensioned in such a fashion to guarantee an interlocking 
engagement between the wings 15 of the wing component 4 into the window 16 
of the window component 3. The wing component 4 is movable and the window 
component 3 is stationary in the measuring cell 1 in the embodiment in 
accordance with FIGS. 1 through 3. Other embodiments are possible with 
which the wing component 4 is stationary and the window component 3 is 
movable or in which a relative motion between the window component 3 and 
the wing component 5 is effected. 
FIG. 4 shows a schematic plan view, from below, of the measuring cell 1 in 
accordance with the invention having a mixing cross configuration 2 in 
accordance with FIGS. 1 through 3. The measuring cell 1 has a cylindrical 
side wall 14. The mixing cross configuration 2 is disposed in the 
cylindrical measuring cell 1 in such a fashion that a interlocking fitting 
of the mixing cross 2 within the inner surface of the side wall 14 of the 
measuring cell 1 is effected. The central bore 5 of the mixing cross 
configuration 2 and the central axis 6 are disposed coaxially in the 
measuring cell 1. The symmetric cross-shaped configuration allows for a 
division of the measuring cell 1 into four separate chambers 17, 18, 19 
and 20, wherein each chamber has an associated inlet opening 10, 21, 11, 
22. 
In the embodiment in accordance with FIGS. 1 through 4, the inlet openings 
10, 21, 11, 22 are located in the lower component 8 and the outlet 
openings 12, 13 in the upper component 7 of the measuring cell 1. In other 
embodiments, one or a plurality of inlet openings can be formed in the 
upper component of the measuring cell as well as one or a plurality of 
corresponding outlet openings in the lower component of the measuring 
cell. 
In order to operate the measuring cell 1 in accordance with FIGS. 1 through 
4, the movable wing component 4 is rotated about its rotation mounting 9, 
for example in the rotation direction of the arrow 24, up to establishment 
of interlocking engagement of the wings 15 of the wing component 4 in the 
corresponding apertures 16 of the window component 3. In this fashion the 
window openings 16 of the window component 3 are sealed by the wings 15 of 
the wing component 4 to subdivide the measuring cell 1 into four separate 
chambers 17, 18, 19, 20. In this position the reaction liquids are 
introduced into the measuring cell 1 through the inlet openings 10, 21, 
11, 22. For example, when two reaction liquids are to be mixed with each 
other the first reaction liquid is filled into the chambers 18 and 20 
using inlet openings 21 and 22 and the second reaction liquid is 
introduced into chambers 17 and 19 using inlet openings 10 and 11. When 
the measuring cell is prepared in this state and filled up with the 
appropriate reaction liquids and when all electronic, computer, or other 
preparations necessary for carrying out the desired NMR measurement have 
been completed, the two reaction liquids are mixed by rotating the wing 
component 4 about its rotational axis 6. The rotational motion causes the 
wing component 4 to open the windows 16 as a result of which a connection 
is established between the reaction chambers 17, 18, 19 and 20. The 
rotational motion of the wing component 4 simultaneously leads to a rapid 
and homogeneous mixing of the two reaction liquids along the entire 
vertical height of the measuring cell 1. 
With the embodiment in accordance with FIG. 4 it is, for example, possible 
to carry out NMR measurements with at least two components within 
milliseconds. The measurements can also be cyclically repeated. In the 
embodiment according to FIGS. 1 to 4, four mixing chambers are provided 
for, but other embodiments having two mixing chambers or an arbitrary 
other number of mixing chambers are also possible. The mixing cross 
configuration 2 in accordance with figures 1 through 4 is particularly 
well suited for use with a flow-through probe head of a NMR measuring cell 
1. The base plate 8 having inlet bores 10, 11, 21 and 22 has a sealed 
central bore for the acceptance of the rotational axis 6 of the wing 
component 4. In accordance with the embodiments according to FIGS. 1 
through 4, the lid plate 7 has drain bores 12, 13. The number of inlet 
bores 11, 21, 33 and drain bores 12, 13 correspond to the number of 
chambers 17, 18, 19, 20 of the mixing cross 2, wherein the embodiment of 
FIG. 4 has four inlet 10, 21, 11, 22, four outlet openings and four 
chambers 17, 18, 19, 20. 
The measuring cell can be manufactured from a glass tube and have a height 
of 30 mm and a diameter of 8 mm. The mixing cross 2 can have two, three or 
more windows 15 and wings 16 and is ideally manufactured from 
susceptibility-compensated glass or from material having low proton 
content. The number of wings 15 of the wing component 4 corresponds to the 
number of windows 16 of the window components 3 and the central part of 
each wing 15 has a bore for acceptance of the rotation axis 6. It is 
advantageous when the wings 15 are cut out of the windows 16 of the mixing 
cross configuration 2 in order to guarantee optimal sealing. The mixing 
wings 15 are also preferentially manufactured from a 
susceptibility-compensated glass or from material with low proton content. 
The axis 6 serves for attachment of the mixing wings 15 and is rotated by 
controlled rotation of the wings 15 using a drive mechanism (not shown), 
wherein the rotation axis 6 is also preferentially manufactured from 
material of low proton content or from compensated glass. The mixing cross 
mechanism 2 drive is preferentially disposed outside of the measuring 
region. 
The shape of the mixing cross 4 having, for example, two, three, four or 
more chambers 17, 18, 19, 20 allows for variation of the number and 
fractioning of the starting elements. The chambers 17, 18, 19, 20 are 
initially separated from each other and closed by the mixing wings 15. The 
inlets 10, 11, 21, 22 and outputs 12,13 of the chambers 17, 18, 19, 20 are 
connected to the base of the probe head by means of capillaries. The 
chambers 17, 18, 19, 20 can be filled by injection or, preferentially, by 
pumping. Following the technical preparations of the starting elements as 
well as the reagent, mixing is effected through a single rapid rotation of 
the mixing wings through, for example, 90.degree., 180.degree., 
270.degree. or 360.degree.. The measurement can start directly following 
rotation. This procedure is effected in such a fashion that it can run 
completely automatically and be repeated as often as desired. 
A second embodiment in accordance with the invention is shown in FIGS. 5 
and 6. The measuring cell 30 in accordance with the FIG. 5 has an upper 
component 31, a lower component 32 as well as a side wall 33 connecting 
the upper component 31 and the lower component 32. The side wall 33 is, 
for example, a hollow cylinder and a mixing plunger 40 is disposed 
centrally within the measuring cell 30. The mixing plunger 40 comprises a 
hollow cylinder 41 as well as a base 44. The base 44 has a central bore 46 
which communicates with an inner region 42 of hollow cylinder 41. Bores 45 
which travel diagonally through a lower portion of the base 44 cause an 
improved mixing of the reaction liquids as described below. The lower 
component 32 has a first inlet opening 34 which communicates with the 
central bore 46 of the base 44 or with the inner region 42 of the hollow 
cylinder 41. A second inlet opening 35 is disposed in the lower component 
32 in such a fashion that it communicates with an outer region 47 of the 
measuring cell. In the embodiment in accordance with FIGS. 5 and 6, an 
outlet opening 36 for the outer reaction liquid is provided for in the 
upper component 31 of the measuring cell 30. A piston bore 53 serves as an 
outlet opening for the starting elements in the inner region 42 of the 
hollow cylinder 41. 
A mount 51 is securely disposed on the upper component 31 of the measuring 
cell 30 and comprises a piston 52 having a central bore 53. The central 
bore 53 communicates with the inner region 42 of the hollow cylinder 41. 
The mixing plunger 40 has a disc-shaped device 43 at its upper end 
disposed in an interlocking fashion within the mount 51. The hollow 
cylinder 41 of the mixing plunger 40 is guided through an opening 50 in 
the upper component 31. 
A seal 60 is provided for between the base 44 and the lower component 32 in 
order to separate the inner region 42 from the outer region 47 in a 
sealing fashion. Additional seals 61 and 63 separate the inner wall of the 
cylinder 41 from the outer wall of the piston 42 in a sealing fashion. 
Appropriate seals 62, 63 are provided for in order to seal the outer 
surface of the cylinder 41 with respect to the inner wall of the opening 
50. A seal 65 is provided for around the outer periphery of the disc 43 to 
seal same with respect to the inner wall of the mount 51. 
FIG. 6 shows the embodiment according to FIG. 5 but with the mixing plunger 
40 withdrawn in the upper direction into the mount 51. 
In order to operate the measuring cell configuration according to FIGS. 5 
and 6, the mixing plunger 40 is initially lowered in a sealing fashion 
using seal 60, wherein the base 44 seats on the upper surface of the lower 
component 32. In this fashion the measuring cell 30 is subdivided into two 
separate chambers 42 and 47 which are sealed relative to each other. A 
first reaction liquid is introduced through the first inlet opening 34 or 
the central bore 46 into the inner region 42 of a hollow cylinder 41. In 
addition a second reaction liquid is introduced into the region 47 outside 
of the hollow cylinder but within the inner side wall of the measuring 
cell 30 by means of the second inlet opening 35. After the inner chamber 
42 and the outer chamber 47 have been prepared and filled with reaction 
liquid, the mixing plunger 40 is pulled upwardly into the position shown 
in FIG. 6. The piston 52 drives the first liquid out of the inner region 
42 of the cylinder 41 to flow out through the central bore 46 of the base 
44. The base 44 can be provided with special bores 45 in order facilitate 
a more rapid and homogeneous mixture between the first and the second 
reaction liquids. 
The movable plunger configuration 40 according to FIGS. 5 and 6 is also 
suitable for carrying out cyclically repeatable NMR measurements between 
at least two components in milliseconds following mixture. The base plate 
32 of the measuring cell 30 has a off-center inlet bore 35 as well as a 
central bore 34 for filling the plunger 40. In the embodiment according 
FIGS. 5 and 6, the lid plate 31 has a single off-center drain bore 36 as 
well as a central bore 53 for the plunger overflow. The measuring cell 30 
is preferentially manufactured from glass and comprises a glass tube of 
approximately 30 mm in height and 8 mm in diameter. It is advantageous 
when the plunger configuration 40 according to FIGS. 5 and 6 is made from 
plastic or glass having low proton content and comprises a special base 
configuration 44 for optimal mixing. A pneumatic unit for motion of the 
plunger 40 from the filling position in accordance with FIG. 5 into the 
measuring position in accordance with FIG. 6 can be advantageously 
disposed outside the measuring region. A sealing hollow guide pipe and 
o-ring seals can be arranged in FIGS. 5 and 6 according to need. 
The selection of the inner diameter of the plunger 40 can be used to 
determine the ratio between the starting elements and the reagent. In the 
position in accordance with FIG. 5 the plunger 40 is closed by means of 
pressure on the disc 43 and both reagents are initially separated from 
each other. The inlets and outlets of the two chambers 47, 42 are 
connected to the probe head base by means of capillaries. The filling-up 
of the chambers 47 and 42 can be effected by means of injection or, 
ideally, using pumps. After NMR technical preparations of the starting 
elements and the reagents, mixing is effected through a rapid raising of 
the plunger 40 into the mount 51. This can be effected using pressurized 
gas in a lower pneumatic unit or through release of a biased spring. A 
special design of the base of the plunger 44, for example having diagonal 
bores 45, can facilitate an optimal mixing between both substances. 
Directly following the lifting of the plunger 40, the measurement is 
started. This procedure is configured in such a fashion that it can 
operate completely automatically and be repeated as often as desired. 
The at least two reaction liquids can be stored in the measuring cell for 
pre-polarization and can be mixed following a certain pre-polarization 
time. A symmetric configuration of the at least partially movable wall 
facilitates the minimization of susceptibility perturbations. Although the 
embodiments describe the utilization of the mixing cell for two reaction 
liquids other embodiments and applications of the measuring cell in 
accordance with the invention for more than two components are possible.