JPH0236179B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid chromatograph, and more particularly to a liquid chromatograph that can be used even when a sample contains solid suspended substances, such as muddy water in a muddy water construction method.

As is well known, liquid chromatographs are used for qualitative and quantitative analysis in a wide range of fields, such as the analysis of organic and inorganic substances and the analysis of biological substances, and the fields of their application are increasingly expanding.

By the way, there are other fields that require qualitative and quantitative analysis, such as quality control of muddy water used in muddy water construction methods in civil engineering and construction, analysis of sludge, quality control of ready-mixed concrete, and management of various types of water and wastewater. The liquid to be measured often contains solid suspended matter. In such cases, conventionally, the sample has been subjected to pretreatment such as centrifugation or filtration to remove suspended substances, and then subjected to liquid chromatography analysis. However, the above-mentioned pretreatment requires a lot of effort and time.
There was a problem that analysis operations were complicated and inefficient. Moreover, the suspended solids contained in fresh concrete and mud water are small particles with a size of about 0.01 to 74 μm, so they pass through ordinary filter media such as nylon, making it practically impossible to remove suspended solids by filtration. I was in a situation. In particular, when analysis of samples containing suspended solids is required, analysis operations are often performed at the work site, such as when controlling muddy water or quality control of ready-mixed concrete. It was hoped that an analytical method would emerge that did not require .

The present invention was made in view of the above circumstances, and
It is an object of the present invention to provide a liquid chromatograph that can measure samples containing suspended solids, such as muddy water in muddy water construction methods, without requiring complicated pretreatment.

In order to achieve this objective, the present invention provides a pre-column filled with porous glass beads in front of a separation column in a liquid chromatograph, and uses this pre-column to remove suspended substances in a sample. This is what I did.

The present invention will be explained below based on embodiments shown in the drawings.

Figures 1 to 3 are diagrams showing one embodiment of the present invention, and show an example in which the present invention is applied to an ion exchange chromatograph such as that used for quality control of mud water in muddy water construction methods. It shows.

First, the general structure will be explained. In FIG. 1, reference numeral 1 is an eluent tank, and 2 is a regeneration liquid tank. Liquid feed pipe 3 pulled out from each tank 1, 2,
4 are each connected to a three-way valve 5, and the three-way valve 5 is further connected to the introduction side of a liquid feeding pump 7 via a liquid feeding pipe 6. The three-way valve 5 is
The liquid feeding path from the eluent tank 1 to the liquid feeding pump 7 and the liquid feeding path from the regeneration liquid tank 2 to the liquid feeding pump 7 are selectively switched.

The liquid sending pump 7 sends out the eluent or the regenerating liquid at a predetermined flow rate.
A sample introduction device 8 is connected to the discharge side of.
Furthermore, a pressure gauge 9 and a damper 10 are provided in parallel between the liquid feeding pump 7 and the sample introduction device 8. The damper 10 is provided to prevent pulsating flow of the liquid sent out from the pump 7, and may be an air damper, a blunger damper, or a combination thereof. Pressure gauge 9
As such, it is preferable to use a device equipped with an upper limiter, and it is desirable to protect the device in the event of excessive pressure.

A pre-column 11, a cation removal column 12, and an anion separation column 1 are installed after the sample introduction device 8.
3 are connected in series. A detector 14 for detecting the ion species separated by the anion separation column 13 is provided downstream of the anion separation column 13. A drain tank 15 is provided downstream of the detector 14 for storing drained eluent and regenerating solution after measurement. Further, the output of the detector 14 is supplied to a recorder 16.

Next, the precolumn 11 will be explained in more detail with reference to FIG. The precolumn 11 is formed by filling a column container 20 with porous glass beads 21 as a filler. The column container 20 has a cylindrical portion 22 made of stainless steel at both ends,
Column plugs 23, 24 and joints 25, 25 are provided at each end.
Stainless steel pipes 26, 26 are connected via 25.

In this case, filters may be provided at the entrance and exit openings of the cylindrical portion 22 for the purpose of preventing the filler from flowing out, but in the case of this embodiment,
No filter is provided at the entrance opening of the cylindrical portion 22 (the opening on the left side in the figure) to prevent clogging due to suspended matter. For this reason, a tapered portion 23a whose diameter gradually increases toward the center of the cylindrical portion 22 is formed inside the column stopper 23 on the inlet side. This tapered portion 23a is provided for the purpose of preventing turbulence from occurring in the liquid flow near the inlet opening of the cylindrical portion 22 due to the omission of the filter. In addition, a filter 28 is provided at the exit side opening of the cylindrical portion 22 to prevent the filler from flowing out, as described above.

Packing agent 21 used in the pre-column 11
are porous glass beads, usually with a particle size of 80
~120 mesh and an average pore diameter of about 3000 Å are used. Such particle size and pore diameter are very suitable when using muddy water for muddy construction method or fresh concrete as a sample.

The inner diameter and column length of the pre-column 11 described above can be set according to the amount of suspended solids in the sample, but in order to improve separation performance, it is desirable to set the inner diameter and column length small. .

Next, the sample introduction device 8 will be explained with reference to FIG.

In FIG. 3, reference numeral 30 is a switching valve, and this switching valve 30 has six openings 31 to 3, first to sixth.
6 is provided. An inlet conduit 3 whose one end is connected to the liquid feeding pump 7 is connected to the first opening 31 .
7 is connected. A sampling loop 38 having a predetermined internal capacity is provided between the second opening 32 and the fifth opening 35 .

A sample suction tube 40 whose one end is connected to a vacuum pump 39 is connected to the third mouth portion 33 . A sample introduction tube 42 for introducing the sample from the sample container 41 is connected to the fourth opening 34 . The sixth port 36 is connected to an outlet conduit 43 that delivers the eluent and sample toward the separation column 13 .

In addition, the valve body 30a of the switching valve 30 has three passages 44, 45, 46 that open and close between adjacent openings.
are formed, and by rotating the valve body 30a, adjacent openings 31 to 3 that communicate with each other can be opened.
There are 6 combinations to choose from.
That is, when the passages 44 to 46 are set as shown by solid lines in FIG. 3, the first and second openings 31,
32, third and third mouth parts 33, 34, fifth and sixth
The openings 35 and 36 communicate with each other, and a measurement path is set from the inlet conduit 37 to the outlet conduit 43 via the sampling loop 38. In addition, in the state shown by broken lines in FIG. 3, the second and third openings 32, 33, the fourth and fifth openings 34,
35, the sixth and first openings 36 and 31 communicate with each other, and there is a sampling path leading from the sample container 41 to the vacuum pump 39 via the sample introduction tube 42, the sampling loop 38, and the sample suction tube 40. Set.

Next, the operation of the above liquid chromatograph will be explained.

During measurement, the eluent in the eluent tank 1 is constantly sent to the separation column 13 at a predetermined flow rate by the liquid sending pump 7, similar to a normal liquid chromatograph. A predetermined amount of sample is introduced from the sample introduction device 8 into this steady flow of eluent. The samples used here do not require treatment to remove suspended solids. This introduction of the sample is performed by the following operation of the sample introduction device 8.

First, the switching valve 30 is connected to its passages 44, 45, 4.
6 indicates the second and third openings 32, 33, the fourth and fifth openings 34, 35, and the sixth
and the first openings 36 and 31 are set to communicate with each other. In this state, the eluent is flowing from the first port 31 through the passage 46 to the sixth port 36 . In this state, when the timer 50 is activated, the decompression pump 39 is activated for the time set in the timer 50, thereby causing the sample inside the sample container 41 to be introduced as shown by the dashed arrow in the figure. Tube 42 - Passage 45 - Sampling loop 38 -
Passage 44 - Flows through sample aspiration tube 40 . Here, the set time of the timer 50 may be set to a value equal to or longer than enough to fill the inside of the sampling loop 38 with the sample to be measured.

Next, the valve body 30a is rotated to open the passages 44,
45 and 46 to the positions shown by solid lines in FIG. As a result, the eluent sent from the liquid pump 7 pushes out the sample in the sampling loop 38 through the inlet conduit 37-passage 44 to the outlet conduit 43, and the sample is directed toward the next stage precolumn 11. Sent out.

The eluent into which a predetermined amount of sample has been introduced by the sample introduction device 8 is then introduced into the precolumn 11, where suspended substances contained in the sample are removed.
In other words, components with large particle sizes in the suspended solids are captured and adsorbed between the particles of porous glass beads with an average pore diameter of about 3000 Å, and components with small particle sizes are
Captured and adsorbed within the pores of porous glass beads. Here, the reason why porous glass beads were used as the packing material for the precolumn 11 is that they are highly rigid materials and are not easily affected by the packing state between glass bead particles even when suspended substances are adsorbed. This is because it is difficult to cause blockage in the pipe.

Dissolved components in the sample pass through the pre-column 11 and are sent to the cation removal column 12 together with the eluent. This cation removal column 12 removes cation species that interfere with the separation of anions in the next separation column 13. The eluate containing the sample that has passed through the cation removal column 12 is sent to the anion separation column 13, where it is separated into each ion species by ion exchange with the packing material and sent out.

Each ion species separated by the separation column 13 is sent to the detector 14 together with the eluent, and detected based on the ion concentration and the like. The detection output of the detector 14 is supplied to a recorder 16, thereby obtaining a chromatogram based on retention time and retention capacity.

According to the liquid chromatograph of the present invention as described above, even samples containing suspended solids can be subjected to measurement without the need for complicated pretreatment of removing suspended solids. Analytical operations become very simple. In addition, as the sample introduction device is equipped with a device that guides the sample introduced into a sampling loop with a predetermined volume into the measurement path by operating a valve, it is not necessary to introduce the sample using a conventional microsyringe. Analysis with good reproducibility can be easily performed without requiring any skilled operations.

In the above embodiments, an example in which the present invention is applied to an ion exchange chromatograph has been described, but the present invention is not limited to this, and can be applied to various liquid chromatographs such as a partition chromatograph, a molecular sieve chromatograph, and an Affinity chromatograph. It can also be applied to

Further, although an example is shown in which the sample introduction device includes one sampling loop, a structure may also be adopted in which a plurality of sampling loops with different capacities are provided and a desired sampling loop is selected by operating a valve.

As explained above, the liquid chromatograph of the present invention is provided with a pre-column filled with porous glass beads between the sample introduction device and the separation column, and this pre-column is used to remove suspended particles contained in the sample. Since substances are removed and then subjected to separation in a separation column, there is no need for complicated sample pretreatment, and samples containing suspended solids, such as muddy water in the muddy water method, can be analyzed with simple operations. It can be done efficiently.

Additionally, by providing a filter only at the outlet end of the pre-column and omitting the filter at the inlet end, it is possible to prevent clogging due to suspended solids and maximize the suspended solids adsorption performance of the column itself. At the same time, by forming the inlet end of the pre-column into a tapered part whose diameter increases toward the center of the column, turbulent flow near the inlet end can be prevented and the packing material packed inside the column can be prevented from flowing out. can do.

Moreover, the particle size of the porous glass beads is 80~
120 mesh and average pore diameter of approximately 3000Å
Therefore, even if the suspended solids are as small as 0.01 to 74 μm in particle size, the components with larger diameters will be captured and adsorbed between the particles of the porous glass beads, and the components with smaller diameters will be trapped and adsorbed between the particles of the porous glass beads. It is captured and adsorbed within the pores of the glass beads, and exhibits very good adsorption performance as a whole. Furthermore, porous glass beads have the advantage of being highly rigid and less susceptible to the filling state between glass bead particles even when suspended matter is adsorbed, and therefore less likely to cause blockage in the tube.

Further, the sample introduction device includes a sampling path for introducing the sample into a sampling loop having a predetermined capacity;
The sampling loop is built into the path from the liquid pump to the separation column, and the measurement path is switched by valve operation, so a predetermined volume of sample can be introduced with good reproducibility without the need for skill or individual differences. Therefore, in addition to the above-mentioned advantage of not requiring pretreatment, it is possible to analyze samples containing suspended solids with simple operations, efficiently, and with high accuracy, without the need for complicated operations. It has the advantage of being suitable for use in various sites where the number of applications should be reduced as much as possible.

Next, the present invention will be described in more detail with reference to experimental examples.

Experimental example 1 Using an ion exchange chromatograph with the configuration shown in Figure 1, muddy water (bentonite muddy water) for the muddy water construction method was prepared.
Anion and cation analysis was carried out.

As a pre-column, the inner diameter is 7.5mmφ and the column length is
Particle size 80~ as packing material in 10cm column container
A 120 mesh filled with porous glass beads with an average pore diameter of 3000 Å was used. In addition, the components of the sample used are as follows.

●Sample Bentonite 6.0% Sodium hexametaphosphate 0.2% Tap water remaining The measurement conditions for anions are as follows.

●Anion analysis eluent: Potassium hydrogen phthalate 5mM Sample collection amount: 100μ Flow rate: 1.5ml/mm Anion separation column: Wescan anion column The measurement conditions for cations are as follows.

●Cation analysis eluent: p-phenylenediamine 5mM Hydrochloric acid 5mM Sample collection amount: 100μ Flow rate: 1.5ml/mm Cation separation column: Wescan cation column Analysis of anions and cations under each of the above conditions As a result, the chromatogram shown in FIG. 4 was obtained. In FIG. 4, curve A is an anion chromatogram, and curve B is a cation chromatogram. Regarding these chromatograms,
As a result of comparison and analysis with the chromatogram of a standard sample previously performed, peak C of curve A was identified as Cl ^- and its amount was determined to be 5 ppm. In addition, peak D of curve B was identified and quantified as Mg ²⁺ (5ppm), and peak E was identified as Ca ²⁺ (5ppm).
Quantified.

From the above results, it was confirmed that the liquid chromatograph of the present invention is capable of analyzing ions at a concentration of 5 ppm or less even for samples containing suspended solids (bentonite in this case).

For comparison, when we attempted to analyze anions and cations under the same conditions as above without using a precolumn, the separation column became clogged after one measurement, and the eluent pressure was 250 kg. / ^cm2 or more, and a chromatogram could not be obtained. In addition, the separation column used became unusable.

Experimental Example 2 Measurement and regeneration were repeated under the same conditions as in the anion measurement shown in Experimental Example 1, and the number of measurements and the pressure inside this channel were investigated. The results are shown in FIG.

From this experiment, it was found that the liquid chromatograph according to the present invention can carry out more than 50 measurements of a sample containing suspended solids (bentonite) under the above conditions while keeping the pressure in the flow path below 100 Kg/ ^cm2 . was confirmed.

In addition, after the measurement when the pressure inside the flow path reached 120Kg/cm ² , only the precolumn was replaced and the same measurement was performed again, and the pressure inside the flow path was approximately 0Kg/cm ² again.
It was confirmed that most of the suspended matter was trapped in the precolumn. It has therefore been found that if the pre-column is well maintained, the separation column can be maintained similarly to that of a chromatograph applied to samples free of suspended solids.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a sectional view showing an example of a precolumn,
FIG. 3 is a schematic configuration diagram showing an example of a sample introduction device;
FIG. 4 is a graph showing a chromatograph of anions and cations obtained in Experimental Example 1, and FIG. 5 is a graph showing the relationship between the number of measurements and the pressure in the flow path obtained in Experimental Example 2. . 7...Liquid feeding pump, 8...Sample introduction device, 11
... Precolumn, 13 ... Anion separation column (separation column), 14 ... Detector (detection device), 2
0...Column container, 21...Filling agent, 23a...
Tapered part, 28... filter, 30... switching valve,
37... Inlet conduit, 38... Sampling loop, 39... Decompression pump, 40... Sample suction tube,
42...sample introduction tube, 43...outlet conduit, 44,
45, 46...Aisle.

Claims (1)

[Claims] 1. A liquid pump for quantitatively force-feeding an eluent, a sample introduction device for introducing a sample into the eluent sent from the liquid pump, and a sample introduction device for introducing a sample into the eluent sent from the liquid pump. In a liquid chromatograph comprising a separation column connected to the rear stage and a detection device connected to the rear stage of the separation column, a liquid feeding path connecting the sample introduction device and the separation column,
A pre-column filled with porous glass beads is interposed, and this pre-column is provided with a filter only at its outlet end, and its inlet end is formed into a tapered part whose diameter increases toward the center of the column,
Furthermore, the particle size of the porous glass beads is 80~
120 mesh and average pore diameter of approximately 3000Å
A liquid chromatograph characterized by the following. 2. The sample introduction device includes a sample introduction tube connected to a sample container, a sample suction tube connected to a vacuum pump, a sampling loop having a constant internal volume, and an inlet side connected to the liquid transfer pump. a conduit, an outlet conduit connected to the separation column, and a switching valve, and the switching valve connects a sampling path from the sample introduction tube to the sample suction tube via a sampling loop, and the inlet conduit. 2. The liquid chromatograph according to claim 1, further comprising a passage that can be selectively set to a measurement path extending from the sampling loop to the outlet conduit.