JP2010002185A - Anion analyzer by ion chromatography - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anion analyzer can suppress the variation of a base line originating from a carbonic acid in the analysis of an anion by ion chromatography. <P>SOLUTION: In the ion chromatography for detecting the anion in a sample by a detector 5 after the sample is successively passed through a column 3 and a suppressor 4 together with an eluent, a degassing device 6 is arranged at the rear stage of the suppressor 4 to remove a carbon dioxide in the eluent after having passed through the suppressor 4. By this method, the peak (variation of the base line) originating from the carbonic acid becoming the obstruction of analysis can be suppressed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to ion chromatography.

  In the suppressor type ion chromatograph, as described in Patent Document 1, as a conventional technique, a suppressor that removes ions in the eluent by an ion exchange reaction is provided at the rear stage of the column. It is an ion chromatograph that enables highly sensitive analysis by reducing the background level of conductivity and improving the S / N ratio.

FIG. 3 shows an example of the configuration of a conventional suppressor type ion chromatograph.
In the figure, the eluent supplied from the eluent container 7 is pressurized by the liquid feed pump 1, merges with the sample injected by the sample introduction unit 2, and passes through the column 3, so that the sample becomes each component. It is separated, passes through the suppressor 4 and the detector 5 in this order, and is discharged into the waste liquid container 8. As described above, the suppressor 4 removes ions in the eluent by an ion exchange reaction. As the detector 5, an electric conductivity detector that detects the ion concentration in the eluent by measuring the electric conductivity of the eluent is mainly used.

  In general, it is necessary to remove dissolved gas from the eluent before feeding, and therefore a deaerator (not shown in FIG. 3) is used. An apparatus using a gas-liquid separation membrane is known as a typical degassing apparatus. This is a device that passes an eluent through a tube made of a gas-liquid separation membrane placed under reduced pressure and discharges dissolved gas through the wall of the tube (see, for example, Patent Document 2).

JP 2002-228645 A JP 2000-107510 A

  In the suppressor type ion chromatograph, a carbonate-based eluent is generally used. In this case, a peak derived from the carbonate ion itself in the eluent always appears in the form of a baseline fluctuation on the chromatogram. Usually, the column that elutes where the peak does not affect the measurement is selected and used, or the separation conditions are changed, such as changing the eluent composition. However, it is not always possible to avoid the effects of carbonate ions while maintaining the required separation, and often adequate separation cannot be obtained.

  This invention is made | formed in view of the said situation, and it aims at providing the analyzer which can suppress the baseline fluctuation | variation derived from a carbonate ion in the anion analysis by ion chromatography.

  In order to solve the above-mentioned problem, the present invention is an analyzer that removes carbon dioxide gas in an eluent after passing through a suppressor using an ion chromatograph device in which a deaeration device is arranged at the subsequent stage of the suppressor. . Thereby, the peak (baseline fluctuation | variation) derived from a carbonic acid which becomes interference of an analysis can be suppressed.

  If the separation conditions are changed to avoid the influence of carbonic acid, the analysis time may be extended or the separation of other components may be sacrificed. According to the present invention, the influence of carbonic acid can be reduced without changing the separation conditions. It can be made smaller. As a result, the analysis accuracy of components that elute in the vicinity is improved.

  The present invention is an anion analyzer by ion chromatography having a process of removing carbon dioxide gas in an eluent after passing through a suppressor provided at a subsequent stage of a column.

  FIG. 1 shows an example of an apparatus configuration of an ion chromatograph for carrying out the present invention. In the figure, the same reference numerals as those in FIG. 3 are the same as those in FIG. The configuration shown in FIG. 1 is different from the conventional configuration in that a deaeration device 6 is disposed between the suppressor 4 and the detector 5. As the degassing device 6, the above-mentioned gas-liquid separation membrane type device is suitable.

  In the configuration shown in FIG. 1, the behavior of the eluent and the sample from the eluent container 7 to the suppressor 4 is the same as in the conventional example shown in FIG. Carbon dioxide in the eluent is removed as carbon dioxide gas in the gas device 6. As a result, the carbonic acid-derived peak (baseline fluctuation) is hardly seen on the chromatogram output from the detector 5, thereby preventing the analysis from being hindered.

FIG. 2 shows an actual analysis result according to the present invention in comparison with an analysis result of the same sample by the conventional method.
In the figure, the upper chromatogram shows the result of analysis using the method of the present invention, that is, the apparatus shown in FIG. 1, and the lower chromatogram shows the result of analysis using the conventional method, that is, the apparatus shown in FIG. In the figure, A, B and B ′ are peaks derived from carbonic acid in the eluent, and it can be clearly seen that according to the method of the present invention, the peak derived from carbonic acid is significantly smaller than that of the conventional method.

Separation conditions for ion chromatography for obtaining the above analysis results are as follows.
Column: Shim-packIC-SA3
250mmL × 4.0mmID
Eluent: 3.6 mmol / L sodium bicarbonate Flow rate: 0.8 mL / min
Column temperature: 45 ° C
Sample introduction amount: 50 μL
Detector: Shimadzu CDD-10A

  The degassing device 6 is not limited to the gas-liquid separation membrane type described above, and any degassing type based on other principles can be used as long as it is an on-stream type.

  The present invention can be used for ion chromatography.

It is a figure which shows the example of an apparatus structure for implementing this invention. It is a figure which shows the analysis example by this invention. It is a figure which shows the conventional apparatus structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid feed pump 2 Sample introduction part 3 Column 4 Suppressor 5 Detector 6 Deaerator 7 Eluent container 8 Waste liquid container

Claims (1)

  In an anion analyzer using ion chromatography in which a sample is passed through a column and a suppressor together with an eluent, and then an anion in the sample is detected by a detector, the dioxide dioxide in the eluent is placed at an intermediate position between the suppressor and the detector. An anion analyzer using ion chromatography, comprising a degassing device for removing carbon gas.

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