JP2005300189A - Liquid chromatograph - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve analysis precision and sensitivity of a liquid chromatograph. <P>SOLUTION: The liquid chromatograph 10 is provided with an injector 12, a sample loop 13; a guard column 14; a separation column 15; and a detector (electrical conductivity meter) 16, which are arranged in a thermostatic chamber 11. The liquid chromatograph 10 is provided with heaters 23 and 33 for heating sample water and an eluent, prior to their introduction to the injector 12 so that their temperatures becomes equal to that of the thermostatic chamber 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid chromatography apparatus (liquid chromatograph), and more particularly to a liquid chromatography apparatus having a thermostatic chamber that houses a main body of the liquid chromatography apparatus.

  As liquid chromatography, ion chromatography using an electric conductivity meter as a detector is known. In ion chromatography, the sample water to be measured and the eluent for eluting the sample water are injected into a separation column using a transfer pump, etc., and the solution chromatographed in the separation column is guided to an electric conductivity meter. The component analysis of the sample water is performed by measuring its electrical conductivity. When quantitatively analyzing ions of sample water using this ion chromatography apparatus, the sample water and eluent are injected into the separation column using an injector.

When measuring the electrical conductivity of the solution flowing out from the separation column with high accuracy and sensitivity with an ion chromatography device, the device body including the separation column and the detector is housed in a thermostatic bath, and the room temperature is kept in the thermostatic bath. Is kept at a higher constant temperature. About an ion chromatography apparatus provided with a thermostat, patent document 1 has description, for example.
JP-A-6-213882

  In a liquid chromatography apparatus equipped with a thermostatic bath, generally, sample water or an eluent kept at room temperature is introduced into a separation column disposed in the thermostatic bath through or without an injector. In this case, since it takes a considerable amount of time for the sample water or eluent that has been kept at room temperature to reach the predetermined temperature set by the thermostatic bath, there is a gradual temperature fluctuation in the solution to be measured. Arise. Such temperature fluctuation not only affects the separation performance of the separation column, but also greatly affects the electrical conductivity detected by the detector. For example, as shown in FIG. The electrical conductivity of the line gradually increases as the measurement time elapses.

  The rising waveform component of the electric conductivity is different in frequency from the pulse-shaped waveform component of the electric conductivity due to the ions to be measured, and can be removed by, for example, filtering the detection signal. However, even if the rising waveform component is removed by a filter or the like, it becomes a factor that gives a certain error to the detection value by the detector, and causes minute noise, swell, drift, etc. in the baseline of the chromatogram. As a result, the stability, reproducibility, and detection sensitivity in chromatography are deteriorated.

  The above problem can be solved by increasing the size or performance of the thermostatic chamber. However, as a result, the entire apparatus becomes larger and the structure becomes complicated, which increases the cost, which is not preferable.

  In view of the above, the present invention improves the conventional liquid chromatography apparatus, reduces noise, undulation, drift, etc. in the baseline of the chromatogram, and thereby detects the measurement target characteristics of sample water with high accuracy and high sensitivity. It is an object of the present invention to provide a liquid chromatography apparatus that can be used.

In order to achieve the above object, a liquid chromatography apparatus of the present invention includes a separation column that receives sample water and an eluent to be measured, a detector that detects characteristics of an effluent that flows out of the separation column, and the separation In a liquid chromatography device comprising a column and a thermostatic chamber that houses a detector and maintains a predetermined temperature,
A means for heating or cooling the sample water and the eluent toward the predetermined temperature outside the thermostat is provided.

  According to the liquid chromatography apparatus of the present invention, the temperature variation of the solution in the separation column or in the vicinity of the detector is achieved by a configuration including means for heating or cooling the sample water and the eluent toward a predetermined temperature outside the thermostat. Therefore, fluctuations in separation performance of the separation column and temporal fluctuations in detection values by the detector are suppressed, and analysis of sample water with high accuracy and high sensitivity becomes possible.

  In addition, since the predetermined temperature maintained in the thermostat is generally higher than room temperature, for example, 30 to 40 ° C., in the liquid chromatography apparatus of the present invention, as a means for heating or cooling, Generally, a warming device that warms the sample water and the eluent is used. However, since the sample water is a sample immediately after the reaction, for example, when the temperature is higher than the predetermined temperature, a cooling device that cools the sample water toward the predetermined temperature is used. Accordingly, as the heating or cooling means, a dedicated heating device, a dedicated cooling device, or a heating / cooling device capable of both heating and cooling can be used for each of the sample water and the elution water. The heating or cooling means preferably heats or cools the sample water and the eluent to the predetermined temperature, but does not have to reach the predetermined temperature or is outside the thermostatic chamber. In consideration of subsequent temperature changes, the temperature may be increased or decreased to a temperature somewhat higher than the predetermined temperature (for example, a temperature higher by 1 to 10 ° C.).

  Further, in the case where a thermostatic chamber between the separation column and the detector is provided with a suppressor that removes predetermined ions from the effluent of the separation column using a removal liquid, the removal liquid is removed from the thermostatic bath. It is also a preferable aspect of the present invention to further include means for heating or cooling toward the predetermined temperature. Similarly, the temperature fluctuation of the solution in the vicinity of the detector is suppressed.

  The means for heating or cooling the sample water, the eluent, and the removal liquid can include a common temperature control means for commonly controlling the temperatures of the sample water, the eluent, and the removal liquid. In this case, for example, in the heating device, heaters can be prepared individually, and only the temperature control device can be shared, or the heater itself can be shared. Furthermore, the sample water, the eluent, and the removal liquid can be heated or cooled in a common thermostat.

  In place of the above, the means for heating or cooling the sample water, the eluent, and the removal liquid may include a temperature control means for individually controlling the temperature of the sample water, the eluent, and the removal liquid. .

  When the means for heating or cooling the sample water, the eluent, and the removal liquid is a heating device, at least one of the sample water, the eluent, and the removal liquid heated by the heating device is used. It is also a preferable aspect of the present invention to provide a degassing means for degassing before receiving in the separation column. By deaeration after heating, the deaeration efficiency in the deaerator is improved. Here, the deaeration means may include an exhaust means commonly provided for the deaeration of the sample water, the eluent, and the removal liquid, or may be individually provided for each deaeration. You may provide the exhaust means provided.

  Hereinafter, with reference to the drawings, the present invention will be described in more detail based on exemplary embodiments of the present invention. FIG. 1 is a block diagram showing an ion chromatography device constituting a liquid chromatography device according to a first embodiment of the present invention. The ion chromatography apparatus 10 includes an apparatus main body housed in a thermostat 11, a sample water supply unit 21 that supplies sample water that is a measurement target liquid to the apparatus main body, and an eluent that supplies an eluent to the apparatus main body. And a supply unit 31.

  The apparatus main body accommodated in the thermostat 11 includes an injector 12 for supplying an eluent and sample water, a sample loop 13 for measuring a predetermined amount of sample water, and a front column for receiving the eluent and sample water. , A separation column 15 that is disposed downstream of the guard column 14 and separates sample water into components, and a detector that measures the electrical conductivity of the solution flowing out of the separation column 15 (electric conduction) Rate meter) 16. In the separation column 15 and the guard column 14, for example, an anion exchanger is accommodated.

  The thermostatic chamber 11 includes a heater and a temperature control device (not shown), and includes an injector 12, a sample loop 13, a guard column 14, a separation column 15, a detector 16, and a pipe for connecting them. Are integrally stored, and the whole is kept at a constant temperature of 35 ° C., for example.

  The sample water supply unit 21 includes a sample water tank 22 that stores sample water, a heater 23 that heats the sample water to a predetermined temperature of 35 ° C. or a slightly higher temperature (for example, 40 ° C. higher by 5 ° C.), and heating A deaeration device 24 that removes bubbles from the later sample water and a sample water transfer pump 25 for transferring the sample water are connected by a pipe in this order, and the sample water is directed from the sample water transfer pump 25 toward the injector 12. Supply. The heater 23 may be provided with a separate temperature control device, or a heater with a temperature control function may be used. The sample water contains, for example, a plurality of anions such as chloride ions, nitrite ions, nitrate ions, phosphate ions, sulfate ions, and these anions are quantitatively analyzed by this chromatography apparatus.

The eluent supply unit 31 removes bubbles from the eluent tank 32 that contains the eluent, the heater 33 that warms the eluent to a predetermined temperature of 35 ° C. or slightly higher, and the heated eluent. The deaerator 34 and the eluent transfer pump 35 for transferring the eluent are connected by a pipe in this order, and the eluent is supplied from the eluent transfer pump 35 toward the injector 12. The heater 33 may be provided with a separate temperature control device, or a heater with a temperature control function may be used. The eluent is, for example, a mixed solution of Na ₂ CO ₃ and NaHCO ₃ .

  When quantitatively analyzing each ion contained in the sample water by the liquid chromatography apparatus 10, first, the apparatus main body is preheated to 35 ° C. in the thermostatic chamber 11. Next, the injector 12 is switched to the sample water supply side (solid line side), sample water is supplied from the sample water tank 22 while being heated, and a predetermined amount of sample water is collected using the sample loop 13. Next, the injector 12 is switched to the sample water injection side (dotted line side), and a predetermined amount of sample water collected is injected into the separation column 15 via the guard column 14. Each ion in the sample water is captured by an ion exchanger in the separation column 15.

  Subsequently, the injector 12 is switched to the solid line side, the eluent is supplied from the eluent tank 32 while being heated, and is introduced into the separation column 15 via the injector 12 and the guard column 14. By introducing the eluent, the sample water flows out toward the detector 16 while being separated for each ion component in the separation column 15, and the electric conductivity determined by the amount of each ion component is measured by the detector 16. .

  In the liquid chromatography apparatus according to the present embodiment, the sample water and the eluent are heated to 35 ° C., which is the same temperature as the set temperature of the thermostat 11 or slightly higher, before being introduced into the injector 12. Therefore, temperature fluctuations of the solution and the apparatus are suppressed during analysis. As a result, stable separation of ion components in the separation column 15 becomes possible, and the electrical conductivity of the effluent detected by the detector 16 is kept stable, so that the accuracy and sensitivity of ion detection are improved.

  FIG. 2 shows an ion chromatography apparatus constituting the liquid chromatography apparatus according to the second embodiment of the present invention in the same manner as FIG. In this embodiment, in addition to the configuration of the apparatus main body of the first embodiment, a known suppressor 17 that removes background ions from the effluent of the separation column 15 is disposed in the subsequent stage of the separation column 15. Yes. A removal liquid for removing background ions is supplied to the suppressor 17 by the removal liquid supply unit 41.

  The removal liquid supply unit 41 removes bubbles from the removal liquid tank 42 that contains the removal liquid, the heater 43 that heats the removal liquid to a predetermined temperature of 35 ° C. or a slightly higher temperature, and the heated removal liquid. The deaeration device 44 to be connected to the removal liquid transfer pump 45 for transferring the removal liquid are connected in this order by piping. In the present embodiment, the removal liquid supplied from the removal liquid tank 42 is heated by the heater 43 and set to the same temperature 35 ° C. as the set temperature of the thermostat 11 or slightly higher. Bubbles are removed from the heated removal liquid by the deaeration device 44 and supplied to the suppressor 17 in the thermostat 11. Other configurations are the same as those of the first embodiment.

  According to the liquid chromatography apparatus according to the present embodiment, the background ions are removed from the effluent flowing out from the separation column 15, so that it is possible to detect ion components with higher sensitivity. Here, the temperature of the solution detected by the detector 16 is suppressed by heating the removal liquid to about 35 ° C. and supplying it to the suppressor 17, and the ion detection is performed as in the first embodiment. The accuracy and sensitivity of the are improved. Further, since the heater 43 is disposed in front of the deaeration device 44, the deaeration efficiency of the removal liquid is improved.

  FIG. 3 shows an ion chromatography apparatus constituting a liquid chromatography apparatus according to the third embodiment of the present invention. In this embodiment, a concentration column 18 is provided in place of the sample loop 13 in the second embodiment. Other configurations are the same as those of the second embodiment. The concentration column 18 concentrates the sample water having a low concentration as it is to a desired concentration, and introduces it into the separation column 15 via the injector 12 and the guard column 14. This compensates for insufficient sensitivity of ion detection in the detector 16.

  In order to confirm the effect of the present invention, anions in the sample water were detected using the liquid chromatography apparatus according to the third embodiment. FIG. 4 shows the electrical conductivity, which is the measured output of the detector 16, as a function of time. For comparison, the electric conductivity detected by a conventional liquid chromatography apparatus in which none of the sample water, the eluent, and the removal liquid is heated is shown in FIG. 5 as a similar function.

  In both figures, the change over time in the electrical conductivity is shown with reference to the electrical conductivity at the measurement start time (0 min). In FIG. 4, the anions to be analyzed are chloride ions (5 min), nitrite ions (6 min), bromide ions (9 min), nitrate ions (10 min), phosphate ions superimposed on the baseline electrical conductivity. (12 min), sulfate ions (15 min), and sequentially detected over time. Since the temperature of the solution for detecting the electrical conductivity is stable, it can be understood that the baseline is maintained stably and each ion component can be easily detected.

  In contrast to this, in FIG. 5, since the temperature of the solution increases with time, a drift that gradually increases occurs in the electric conductivity of the baseline. Due to this drift, the accuracy and sensitivity of the detected electrical conductivity are reduced when, for example, bromide ions or phosphate ions are detected. Thus, in the liquid chromatography apparatus of the present invention, the temperature fluctuation of the solution can be suppressed, so that the fluctuation of the measured electric conductivity can be suppressed in addition to the stability of the chromatographic separation in the separation column. The accuracy and sensitivity of the graphic are improved.

  Although the present invention has been described based on the preferred embodiment, the liquid chromatography apparatus of the present invention is not limited to the configuration of the above-described embodiment. Those modified and changed as described above are also included in the scope of the present invention. For example, each heater may be disposed in a corresponding tank.

1 is a block diagram of a liquid chromatography apparatus according to a first embodiment example of the present invention. The block diagram of the liquid chromatography apparatus which concerns on the 2nd Example of this invention. The block diagram of the liquid chromatography apparatus which concerns on the example of the 3rd Embodiment of this invention. The function regarding the measurement time of electrical conductivity which shows the analysis result by the liquid chromatography apparatus of 3rd Example. A function related to the measurement time of electrical conductivity showing the result of analysis by a conventional liquid chromatography apparatus.

Explanation of symbols

10: Liquid chromatography device 11: Thermostatic bath 12: Injector 13: Sample loop 14: Guard column 15: Separation column 16: Detector (electric conductivity meter)
17: Suppressor 18: Concentration column 21: Sample water supply unit 22: Sample water tank 23: Heater 24: Deaeration device 25: Sample water transfer pump 31: Eluent supply unit 32: Eluent tank 33: Heater 34: Deaeration Device 35: Eluent transfer pump 41: Remover supply unit 42: Remover tank 43: Heater 44: Deaerator 45: Remover supply pump

Claims (9)

A separation column that receives sample water and an eluent to be measured, a detector that detects the characteristics of the effluent that flows out from the separation column, and a thermostat that contains the separation column and the detector and maintains a predetermined temperature. In a liquid chromatography apparatus comprising:
A liquid chromatography apparatus comprising: means for heating or cooling the sample water and the eluent toward the predetermined temperature outside the thermostatic chamber.   A suppressor that is disposed in the thermostat between the separation column and the detector and removes predetermined ions from the effluent using a remover, and the remover is disposed outside the thermostat. The liquid chromatography apparatus according to claim 1, further comprising means for heating or cooling toward the temperature of the liquid chromatography apparatus.   The means for heating or cooling the sample water, eluent, and removal liquid comprises common temperature control means for commonly controlling the temperature of the sample water, eluent, and removal liquid. The liquid chromatography apparatus according to the description. The means for heating or cooling the sample water, eluent, and removal liquid heats or cools the sample water, eluent, and removal liquid in a common thermostat. Liquid chromatography device.   The means for heating or cooling the sample water, eluent, and removal liquid comprises temperature control means for individually controlling the temperature of the sample water, eluent, and removal liquid. Liquid chromatography device.   The means for heating or cooling the sample water, the eluent, and the removal liquid is a heating apparatus, and at least one of the sample water, the elution liquid, and the removal liquid heated by the heating apparatus is used. The liquid chromatography apparatus according to claim 2, further comprising a deaeration unit for deaeration before receiving the separation column.   The liquid chromatography apparatus according to claim 6, wherein the deaeration unit includes an exhaust unit commonly disposed for deaeration of the sample water, the eluent, and the removal liquid.   The liquid chromatography apparatus according to claim 6, wherein the deaeration unit includes an exhaust unit that is individually provided for each deaeration of the sample water, the eluent, and the removal liquid.   The means for heating or cooling the sample water and the eluent is a heating device, and the sample water and eluent heated by the heating device are removed before being received in the separation column. The liquid chromatography apparatus according to claim 1, further comprising a deaeration means for gassing.

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