JPH0721486B2 - Packed column for liquid chromatography - Google Patents

Description

TECHNICAL FIELD The present invention relates to a packed column for a liquid chromatograph.

[Prior Art] Liquid chromatographs include a column packing device integrally incorporated and a liquid chromatograph separated and independent. In the former case, the apparatus becomes large in size, and the sample separation work is stopped while the chromatographic tube is filled with the stationary phase, so that a lot of time is lost. The latter complements the former's drawbacks.A column (packed column) in which the stationary phase is filled and held at a prescribed pressure is created using an independent column packing device as needed, and set in a liquid chromatograph as needed. To use.

The most important factors that influence the performance of packed columns for liquid chromatographs are the pressure distribution and pressure magnitude of the stationary phase. The more uniform the pressure distribution, the better the performance, but
If the pressure of the stationary phase is not uniform, a space will be created, a channeling bypass phenomenon will occur, and due to the wall flow effect, the flow path length from the upper end of the column to the outflow from the lower end of the sample will vary depending on the location. Also, the transit time may differ due to the density difference of the stationary phase. Therefore, the separation performance (theoretical plate number) of the packed column is significantly reduced. Further, if the pressure of the stationary phase is low, the flow rate of the eluent cannot be increased, so that the separation time becomes long and the efficiency of the separation work is reduced.

As shown in FIG. 5, a conventional general packed column 1
Is packed in a cylindrical chromatographic tube 2 with a stationary phase C, and the stationary phase C is pressed from one side by a piston 3 to compress the pressure, and after increasing the pressure, the piston 3 is attached to the chromatographic tube 2 by some method. It is fixed so that the pressure is maintained.

[Problems to be Solved by the Invention]

However, in the packed column 1, when the stationary phase C is compressed by the piston 3, the stationary phase C moves relatively to the inner wall of the chromatographic tube 2, so that a frictional force is generated, which allows uniform compression. There wasn't. That is, as shown in FIG. 5, the axial pressure Px sharply decreased with the distance Sx from the piston 3. This tendency is particularly large in long packed columns.

The present invention was developed in view of the above points, and an object thereof is to obtain a packed column for a liquid chromatograph capable of uniformly distributing the pressure of the stationary phase packed in the chromatographic tube.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention is a packed column for a liquid chromatograph in which a stationary phase is pressure-packed in a chromatographic tube, and the chromatographic tube is made of a material having a small longitudinal elastic coefficient such as synthetic resin or hard rubber. The chromatographic tube is inserted into an outer cylinder made of a hard material, and the chromatographic tube is prevented from being deformed in the radial direction when the stationary phase is pressurized and filled in the chromatographic tube. The outer circumference of the tube is held by a coil.

[Work]

Therefore, the stationary phase can be uniformly pressurized and filled without generating a frictional force between the stationary phase and the inner wall of the chromatographic tube.

〔Example〕

 Hereinafter, the present invention will be described with reference to the drawings.

First, one embodiment of the packed column will be described with reference to FIG.

The packed column 10 includes a chromatographic tube 11 in which the stationary phase C is filled, an outer cylinder 12 for housing the chromatographic tube 11, a flange 13 fixed to one end of the outer cylinder 12, and an outer cylinder 12. It is composed of a piston 14 inserted from an end opening, a cap 15 for fixing the piston 14 to the outer cylinder 12, and the like.

Chromatography tube 11a, various materials having a small longitudinal elastic coefficient such as synthetic resin and hard rubber, for example, those formed into a cylindrical shape from engineering plastics such as fluororesin (for example, Teflon (registered trademark)), etc. The outer cylinder 12, the flange 13, the piston 14, the cap 15 and the like are made of a hard material such as stainless steel.

Chromatography tube 11 has small diameter parts 11a, 11b formed on the outer circumference of both ends.
In addition, the taper ring 16 having a slit 16a and having a variable diameter
Then, the rings 17 having the grooves 17a are respectively fitted and the coil 18 is wound between the rings 16 and 17 and is inserted into the outer cylinder 12. The coil 18 is attached so that its inner circumference is in close contact with the outer circumferential surface of the chromatographic tube 11, and both ends 18a, 18a are respectively engaged with the slit 16a of the taper ring 16 and the groove 17a of the ring 17. It is said to be unable to rotate.

The outer cylinder 12 has a cylindrical shape in which the chromatographic tube 11 can be mounted, and is formed to be longer than the chromatographic tube 11, and has a piston shape.
A male screw 12a is screwed on the outer peripheral surface of the insertion side 14 (upper side in FIG. 1). In addition, the fixed portion side of the outer cylinder 12 (first
A flange portion 12b for fixing the flange 13 with a bolt 19 is formed on the outer periphery of the lower end (in the drawing), and the body portion further has an inlet 12c and an outlet 1c for hot water for heating the stationary phase.
2d is formed.

A small diameter passage 20 is formed in the axial center of the flange 13 fixed to the outer cylinder 12, and a radial groove 20a is formed at the inner end of the small passage 20 to hold the stationary phase C. A filter 21 is provided for this purpose. A female screw 20b for connecting the sample and eluent outlet pipes is formed at the outer end of the small diameter passage 20. The outer peripheral surface of the flange 13 has a small diameter portion 13a corresponding to the inner diameter of the chromatographic tube 11, and the outer cylinder 1
2 corresponding to the inner diameter of 2 and the flange portion 12b of the outer cylinder 12
It is formed in three steps of the large diameter portion 13c fixed to the. Further, an O-ring 22 is provided on the outer circumference of the small-diameter portion 13a to abut on the inner circumference of the chromatographic tube 11 to prevent leakage, and on the outer circumference of the middle-diameter portion 13b, abut on the inner circumference of the outer cylinder 12 to leak. An O-ring 23 is provided to prevent this.

Then, the small diameter portion 13a on the inner end side of the flange 13 is inserted into the outer cylinder 12 together with the chromatographic tube 11 in a state of being inserted into the end portion of the chromatographic tube 11, and the medium diameter portion 13b is the end portion of the outer cylinder 12. The small diameter part 13c by tightening the large diameter part 13c to the collar part 12b.
A step portion 13d between the intermediate diameter portion 13b and 13a axially presses the end portion of the chromatographic tube 11 and the taper ring 16, and the inclined surface portion 12e formed on the inner circumference of the end portion of the outer cylinder 12 is tapered. The diameter of 16 is reduced, the end of the chromatographic tube 11 is pressed toward the inner peripheral side, and the end of the chromatographic tube 11 is pressed against the outer periphery of the small diameter portion 13a of the flange 13 to fix the chromatographic tube 11.

On the other hand, the piston 14 is formed in a shape slidable in the outer cylinder 12 in the axial direction, and the outer peripheral surface of the piston 14 is
A small-diameter portion 14a corresponding to the inner diameter of the chromatographic tube 11, a large-diameter portion 14b corresponding to the inner diameter of the outer cylinder 12 and a tip thereof are formed in three stages of a small-diameter shaft portion 14c protruding from the end of the outer cylinder 12. . A small-diameter passage 24 similar to the flange 13 is formed in the center of the piston 14 in the axial direction, and a radial groove 24a is formed at the inner end thereof to hold the stationary phase C. A filter 25 is provided, and an internal thread 24b for connecting sample and eluent inlet piping is formed at the outer end.
Further, O-rings 26 and 27 similar to the flange 13 are provided on the outer circumferences of the small diameter portion 14a and the large diameter portion 14b, respectively.

Further, the cap 15 has the piston 14 at the center of the top plate portion 15a.
An insertion hole 15b for inserting the small-diameter shaft portion 14c is formed, and a female screw 15d that is screwed with the male screw 12a of the outer cylinder 12 is screwed on the inner periphery of the cylindrical portion 15c, and the outer peripheral surface of the female screw 15d is screwed. A handle 15e for use is projected. The cap 15 is configured such that the female screw 15d is screwed into the male screw 12a of the outer cylinder 12 and tightened, so that a cylindrical collar 28 disposed between the outer end surface of the piston 14 and the top plate portion 15a is interposed. Press the piston 14,
The chromatographic tube 11 and the stationary phase C inside the chromatographic tube 11 are axially compressed.

In order to fill the packed column 10 with the stationary phase C, the chromatographic tube 11 is first installed in the outer cylinder 12, and the stationary phase C is placed inside the outer tube 12.
With an image body filled with (powder), the piston 14 is axially pressed by a column packing device described later to compress the chromatographic tube 11 and the stationary phase C together, and the chromatographic tube 11 is elastically deformed in the axial direction. And the stationary phase C is compressed. And stationary phase C
When the pressure reaches a predetermined pressure, stop pushing the piston 14 there, and hold the position of the piston 14 as it is.
Tighten the cap 15 until the collar 28 hits the piston 14.

The stationary phase C is compressed and the chromatographic tube 11 is used.
By elastically deforming, the inner wall of the chromatographic tube 11 also deforms and moves as the stationary phase C compresses, so there is no relative movement in the axial direction between them, so no frictional force is generated. The stationary phase C can be uniformly compressed.
Further, since the stationary phase C can be uniformly compressed along with the chromatographic tube 11 over the entire length in the axial direction, it is possible to reduce the occurrence of pressure loss in which the pressure of the stationary phase C decreases with the passage of time. Further, since the position of the piston 14 can be held by the cap 15 and the collar 28, the pressure of the stationary phase C can be held for a long time, and the pressure loss can be supplemented by tightening the cap 15.

Further, by compressing the chromatographic tube 11 in the axial direction, the adhesion between the inner peripheral wall of the chromatographic tube 11 and both O-rings 22 and 27 is improved by the action of the taper ring 16 and the ring 17, and an accident such as liquid leakage may occur. Can be prevented. Further the coil 18
Does not hinder the elastic deformation of the chromatographic tube 11 in the axial direction, but has the function of preventing the radial expansion of the chromatographic tube 11, and further forms the flow path of the hot water for heating the stationary phase. .

The packed column 10 thus formed can be used in the same manner as a conventional packed column. That is, when the injection pipe is connected to the female screw 24b of the piston 14, the sampling pipe is connected to the female screw 20b of the flange 13, and the sample and the eluent are introduced from the injection pipe, the sample and the eluent are
The small diameter passage 24 in 14 passes through the radial groove 24a and the filter 25
To stationary phase C. The separated sample and eluent are collected by the sampling tube from the filter 21 provided at the inner end of the flange 13 through the radial grooves 20a and the small diameter passage 20.

Further, the inlet for hot water for heating the stationary phase formed in the outer cylinder 12
By circulating hot water or hot water into the tubular space between the chromatographic tube 11 and the outer tube 12 using 12c and the outlet 12d, the temperature of the stationary phase C is increased and the efficiency of the column is increased (theoretical plate). Height can be reduced).

Next, an example of a column packing device for packing the stationary phase C in the packed column 10 will be described with reference to FIGS. 2 and 3.

In this column packing device 30, a plurality of chromatographic tube receivers 33 are provided in upper and lower stages in a gate-shaped frame 32 having casters 31 attached to the lower part thereof, and a jack 34 is directed downward at the center of the upper part of the frame 32. It is installed by screwing.

At the end of the rod 34a of the jack 34, the packed column 10
A push rod 35 that pushes the piston 14 downward is screwed. The front of this push rod 35 has a displacement gauge.
36 is attached, and its tip 36a is in contact with a push plate 37 attached to the frame 32. In addition, the jack 34,
A hand pump 39 capable of feeding high-pressure oil via a hose 38 is connected, and the pressure is read by a hydraulic pressure gauge 40.

The packed column 10 has a receiving member 41 that is placed horizontally on any of the chromatographic tubes 33 according to the dimensions of the packed column 10.
The flange 13 is placed on the upper part of the column, and the upper part is fixed to the frame 32 by being sandwiched by two chromatographic tube tilting stoppers 42, 42 having U-shaped notches. Then, the stationary pump C in the packed column 10 can be compressed by gradually feeding the oil to the jack 34 with the hand pump 39.

At this time, in order to compress the stationary phase C in the chromatographic tube 11 to a predetermined pressure, it is necessary to know the piston pressing amount and the pressing force.

FIG. 4 shows the relationship between the piston pushing down amount S [cm] and the pushing down force P [Kg]. The pointer of the displacement gauge 36 when the lower end of the push rod 35 contacts the upper end of the piston 14 of the packed column 10. Adjust the height of the push plate 37 so that the piston push-down amount S = 0 and the piston push-down force P = 0.
The pressure P is calculated from the reading of 36 and the pressure P is calculated from the reading of the hydraulic pressure gauge 40 by the following equation.

P ≒ Pg × A However, Pg: reading of the hydraulic pressure meter [Kg / cm ² ] A: jack working area [cm ² ] The solid line La in Fig. 4 is the piston depression when the packed column 10 is filled with the stationary phase C. It is an operation line showing the relationship between the amount S and the pushing down force P, and the broken line Lb is the relationship between the piston pushing down amount S of only the chromatographic tube 11 and the pushing down force P.
Lc is the relationship between the piston depressing amount S of only the stationary phase C and the depressing force P.

As shown in the figure, in the case of only the chromatographic tube 11, the pushing-down force P increases in proportion to the pushing-down amount S up to the limit value Slim of the pushing-down amount determined by the material of the chromatographic tube 11.

On the other hand, in the stationary phase C, almost no reaction force is generated until the pressing amount S ₁ where the space between the particles of the stationary phase C gradually disappears, and when the pressing amount exceeds S ₁ , the particles of the stationary phase C come into contact with each other. As a result, elastic deformation is started, so that the pushing-down force P rapidly rises.

As a result, the inflection point T is generated at the pressing amount S _{1 on the} operation line indicated by the solid line La obtained by adding the broken line Lb and the dashed line Lc.

Considering here a case where a packed column 10 with a stationary phase C packing pressure of P _K is created, the space between the stationary phase C particles disappears at the pushing amount S ₁ at the inflection point T, and all the particles are adjacent to each other. Since it is considered to be the moment of contact with the existing particles, the filling pressure of the stationary phase C at this time can be regarded as zero.

Therefore, if the pushing-down force at the inflection point T is P _1, and the pushing-down force when the filling pressure of the stationary phase is P _K is P ₂ ,
The increase amount ΔP of the pushing-down force P after the inflection point T is shown by ΔP = P ₂ −P ₁ ……………………… (1), and this increase amount ΔP is the same as that of the chromatographic tube 11. Stationary phase C
The sum of the similar increase amounts ΔP _C (chromatography tube) and ΔP _K (stationary phase) of the respective pushing-down force P of The ΔP _C and ΔP _K can be expressed by the following equations, respectively.

ΔP _K = P _K A _K ……………………………… (3) where A _C : cross-sectional area of the chromatographic tube l _C : chromatographic tube length E _C : longitudinal elastic modulus of the chromatographic tube S ₁ : variable depression amount of flexion point S _2: depressing amount P _K when the filling pressure of the stationary phase becomes P _K: target filling pressure of the stationary phase a _K: cross-sectional area downward force P of the stationary phase is monitored by the pressure gauge 40 Therefore, the inflection point T can be determined by the abrupt change in the increase amount of the deflection of the pressure gauge 40. From the reading of the pressure gauge 40 at that time, when the reading increases by the increase amount ΔP of the reading of the pressure gauge 40 calculated by the following equation, that is, when the reading of the pressure gauge 40 becomes P ₂ , the hand pump 39 sends If the oil is stopped, the filling pressure of the fixed feed C can be set to P _K.

Here, ΔP _C : increase amount of chromatographic tube push-down force calculated by formula (2) ΔP _K : increase amount of stationary phase push-down force calculated by formula (3) A: jack working area (4) In general, since ΔP _C << ΔP _K , the formula (4) can be converted into a simple formula such as ΔP = ΔP _K / A, and can be easily calculated.

That is, the equation (4) can be expressed as follows by substituting the equation (3).

Therefore, the reading P ₂ of the pressure gauge 40 for stopping the oil feeding by the hand pump 39 can be obtained by the following equation from the above equations (5) and (1).

In the above equation (6), since P _K and A _K can be calculated in advance, the end point P ₂ can be easily determined by reading the pressing force P ₁ at the inflection point T with the pressure gauge 40. Can be determined and the stationary phase C can be brought to a predetermined pressure.

The pushing force P ₂ thus obtained stops the oil supply from the hand pump 39, the pushing amount of the jack 34 is maintained as it is, the cap 15 of the packed column 10 is tightened to the outer cylinder 12, and the collar 28 is moved to the piston. The position of the piston 14 with respect to the outer cylinder 12 is fixed by hitting the piston 14. Then, the jack 34 is retracted and the packed column 10 is packed into the column packing device 30.
If removed, the packed column 10 packed with the stationary phase C at a predetermined pressure can be obtained.

It should be noted that, when the pushing amount is about to exceed Slim during filling, the oil feeding is stopped, the stationary phase C is added / increased, and the filling work is restarted.

As a column packing device, a relatively small-scale example is shown, but a large-scale device uses a motor-driven pump with a constant discharge amount, and an electric displacement meter is used to measure the push-down amount S. In addition, a load cell or the like is used to measure the pushing-down force P, and the load cell is loaded into a microcomputer to calculate the amount of change in the pushing-down force P momentarily, where the value suddenly increases (the inflection point mentioned above). It is conceivable to find T) and automatically stop the pumping of oil when the pushing-down force increases by ΔP from there.

〔The invention's effect〕

As described above, the packed column of the present invention is used when a chromatographic tube formed of a material having a small longitudinal elastic modulus is inserted into an outer cylinder formed of a hard material and a stationary phase is pressure-filled in the chromatographic tube. In order to prevent radial deformation of the chromatographic tube, the outer circumference of the chromatographic tube is held by a coil, so the stationary phase can be uniformly compressed, and a high-performance packed column with less pressure loss can be easily performed. Can be obtained. Further, even in a long packed column, the stationary phase can be uniformly pressure-packed, so that a packed column with higher performance can be obtained.

Therefore, it is possible to stably obtain a packed column having excellent performance and to improve efficiency and reliability of sample separation work and the like.

[Brief description of drawings]

FIG. 1 is a sectional view of a packed column showing an embodiment of the present invention, FIGS. 2 and 3 show an example of a column packing device, and FIG. 2 is a front view of the column packing device, and FIG. Is also a side view, FIG. 4 is a diagram showing the relationship between the piston pressing amount S and the pressing force P, and FIG. 5 is an explanatory diagram showing the packing pressure distribution of the stationary phase in the conventional packed column. 10 …… packed column, 11 …… chromatographic tube, 12 …… outer cylinder, 13 …… flange, 14 …… piston, 15 …… cap, 18 …… coil, 21,25 …… filter, 30 …… column packing Device, C ... Stationary phase, P ... Pushing down force, S ...
Depression amount of piston

Claims (1)

[Claims] 1. In a packed column for a liquid chromatograph in which a stationary phase is pressure-filled in a chromatographic tube, the chromatographic tube is formed of a material having a small longitudinal elastic coefficient such as synthetic resin or hard rubber, and the chromatographic tube is formed. The outer circumference of the chromatographic tube was held by a coil in order to prevent radial deformation of the chromatographic tube when the stationary phase was pressure-filled in the chromatographic tube while being inserted into the outer cylinder made of a hard material. A packed column for a liquid chromatograph characterized by.