JP2625001B2 - Chloride ion replacement column and flow injection analyzer using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is used in technical fields such as food analysis, environmental chemistry analysis, medical drug analysis, etc., and a chloride ion-exchange column for measuring chloride ions and the same. The present invention relates to a flow injection analyzer using the method.

[Prior Art] Conventionally, the following method is used for measuring chloride ions.

For practical measurement, volume analysis methods such as the Mohr method, the Horhard method, and the Fajans method are frequently used because they are simple and convenient.

As the instrumental analysis method, a spectrophotometric method such as a mercury (II) thiocyanate method and a diphenylcarbazone method, and an ion chromatography method are used.

As the electrolysis method, an ion electrode method, an electric conductivity method,
Polarographic methods and the like are used.

[Problems to be Solved by the Invention] However, the volumetric method, the absorptiometry method, and the like require a skill in preparing a sample and require a long analysis time, so that there is a problem as a management analysis method in the field.

A method for measuring chloride ions by an ion electrode method, an electric conductivity method, or the like as an electroanalytical method is simple, but is susceptible to other coexisting ionic species and has problems in selectivity and accuracy.

In addition, in the ion chromatography method, although there is selectivity for chloride ions, there are problems such as an expensive column.

Further, in any of the above methods, there is a difficulty in analyzing a sample containing a high concentration of chloride, which involves an operation of dilution.

An object of the present invention is to provide a flow injection analyzer that solves the above problems and a chloride replacement column used for the same.

[Means for Solving the Problems] The present invention provides a chloride ion measuring device that combines the advantages of chemical analysis and instrumental analysis, and uses a stationary phase containing a substance that undergoes a substitution reaction with chloride ions. The reaction product is detected and measured by a flow injection method using a column described as above.

In this column, a substance that undergoes a substitution reaction with chloride ions is filled into a tube as it is in a solid or fine powder form, or a substance obtained by dispersing the substituted substance in a fine powder such as alumina, silica gel, or filter paper is filled in a tube. It is composed.

As a substance that undergoes a substitution reaction with chloride ions, for example,
Examples include silver hexacyanoferrate (III), silver chromate, silver iodate, silver dichromate, silver oxalate, and mercury chloranilate.

For detection of the substitution reaction product, an absorption density method or an electrochemical measurement method such as an ion electrode method, a voltammetry method, a potentiometry method, an electric conductivity measurement method, and a polarographic method is used.

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

(1) Flow injection analyzer FIG. 1 shows a flow injection analyzer.

The carrier 12 in the storage tank 10 is sent by a pump 14 and passes through a chloride ion replacement column 18 together with a sample solution containing chloride ions introduced from a sample injector 16.

The chloride ion exchange column 18 is made of a substance that undergoes a substitution reaction with chloride ions, for example, silver hexacyanoferrate (III)
Silver chromate, silver iodate, silver dichromate, silver oxalate,
A stationary phase containing mercury chloranilate or the like is filled in a tube, and filters are provided at both ends.

Therefore, for example, the following substitution reaction occurs in the chloride ion substitution column 18.

MpAq + qCl ⁻ → MClp + A ^p− Here, MpAq is a substance that undergoes a substitution reaction with a chloride ion, and causes an equivalent substitution reaction with a chloride ion in a mobile phase in a chloride ion substitution column 18 to cause A ^p− In the mobile phase.

Therefore, the concentration of chloride ion can be quantified by measuring the substitution reaction product ^Ap- .

The other displacement reaction product MClq remains in the column or
It is desirable not to affect the detection of ^p- .

(2) How to Make Chloride Ion Replacement Column 18 Next, how to make the chloride ion replacement column 18 that was actually made and used in the following test examples will be described.

A substance that undergoes a substitution reaction with chloride ions, for example, any of silver hexacyanoferrate (III), silver chromate, silver dichromate, silver oxalate, mercury chloranilate, and the like is ground in an agate mortar to form fine powder (particle size). 100-300 mesh).

To this fine powder, a fine powder (particle size: 100 to 300 mesh) such as alumina, silica gel, filter paper, etc., preferably in an amount of 3 to 5 times the weight of the fine powder as a dispersant, is added and mixed well. The proportion of dispersant can be higher than this.

As shown in FIG.
Fill a stainless steel tube 24 of 4.6 mm and length of 50 mm. Sintered filters 26 are arranged at both ends in the stainless steel tube 24, and in the vicinity of the sintered filter 26 between the sintered filter 26 and the stationary phase 22, only the dispersant 28 is put in order to prevent clogging. .
The packing of the stationary phase 22 and the dispersant 28 is preferably performed so that the back pressure of the column is 15 to 20 kg / cm ² or less even at a flow rate of 5 ml / min. The column 18 thus prepared usually has a flow rate of 1 ml /
Under min, the column back pressure is 1-2 kg / cm ² .

When the amount of the dispersant 28 is reduced, the back pressure of the column is increased. When the amount of the dispersant 28 is increased, the back pressure of the column is decreased, but the life of the column is shortened.

In FIG. 2, the other components are the same as those of a liquid chromatography separation column well known to those skilled in the art, 30 is a cap nut, 32 is a rear ferrule, 34 is a front ferrule,
36 is a filter bush, 38 is a dufeather, and 40 is a reducer.

 Hereinafter, test examples of this example will be described.

(3) Test Example 1 The test conditions are as follows.

Carrier 12: 0.05M Ca (NO ₃ ) ₂ solution, flow rate 3ml / min Sample: 10% NaCl solution 5μ Pump 14: manufactured by JASCO Corporation Model 880PU Chloride ion substitution column 18: Substance which reacts with chloride ion Prepared by using powdery silver hexacyanoferrate (III) as a dispersant and powdery filter paper (100 to 300 mesh) as a dispersant.

Detector 20: Visible Ultraviolet Spectroscopic Detector manufactured by JASCO Corporation Model 870-UV Hexacyanoferrate (III) silver undergoes a substitution reaction with chloride ion as shown by the following formula to convert hexacyanoferrate (III) ion. discharge.

Ag ₃ [Fe (CN) ₆ ] + 3Cl ⁻ → 3AgCl + [Fe (CN) ₆ ] ^3- The chloride ion is quantified by measuring the concentration of this hexacyanoferrate (III) ion.

As a result of the measurement, a chromatogram as shown in FIG. 3 was obtained.

In addition, the sample injector is
When 1 μm of sodium chloride solution was injected from 16 and the peak wave height of the chromatogram was plotted against the concentration of sodium chloride solution, the calibration curve shown in FIG. 4 was obtained.
There is a quantitative relationship between the absorbance based on hexacyanoferric (III) ions and the sodium chloride solution, indicating that chloride ion can be quantified by this method.

(4) Test Example 2 The test conditions are as follows.

Pump 14 and detector 20: same as in Test Example 1 Carrier 12: 0.1M NaNO ₃ solution, flow rate 3ml / min Sample: 0.3% NaCl solution 5μ Chloride ion replacement column 18: Powdery substance that reacts with chloride ion Prepared as described above using silver chromate and powdered alumina (100-300 mesh) as a dispersant.

Silver chromate reacts with chloride ions as shown by the following formula to release chromate ions.

Ag ₂ CrO ₄ + 2Cl ⁻ → 2AgCl + CrO ₄ ^2- By measuring the concentration of this chromate ion, the chloride ion is quantified.

As a result of the measurement, a chromatogram as shown in FIG. 5 was obtained.

In addition, the sample injector 16 is
Then, 5 μm of a sodium chloride solution was injected from the sample, and the peak wave height of the chromatogram was plotted against the concentration of the sodium chloride solution to obtain a calibration curve shown in FIG. There is a linear relationship between the absorbance and the concentration of the sodium chloride solution, which indicates that it can be used for quantification of chloride ions.

(5) Test Example 3 The test conditions are as follows.

Pump 14 and chloride ion exchange column 18: same as in Test Example 1 Carrier 12: 0.1M NaNO ₃ solution, flow rate 3ml / min Sample: 5% NaCl solution 1μ Detector 20: Electrochemical detector by chronoamperometry Japan As a result of measuring the reduction current of hexacyanoferrate (III) ion of the substitution reaction product of Model 840-EC manufactured by Spectroscopic Co., Ltd., a chromatogram as shown in FIG. 7 was obtained.

When the reduction current and the concentration of sodium chloride were plotted against the carrier 12 when a sodium chloride solution of 1 μm was injected from the sample injector 16, a calibration curve as shown in FIG. 8 was obtained. From this figure, it can be seen that the chloride ion can be quantified also by the electrochemical measurement method.

(6) Test Example 4 As an application of the present invention to an actual sample, the chloride ion concentration in a commercially available food was measured.

 The test conditions are as follows.

Pump 14, chloride ion exchange column 18 and detector 20: same as in Test Example 1 Carrier 12: 0.05 M Ca (NO ₃ ) ₂ solution The sample used for the analysis was prepared by diluting food without diluting 0.1
The solid matter was filtered through a membrane filter having a pore size of μm. The carrier flow rate and sample injection amount are shown in Table 1 below.
It is as follows.

In order to know the chloride ion concentration, an appropriate concentration of sodium chloride solution was used as a reference before the analysis sample was injected.

The analysis time for one sample was only a few minutes. The measurement results are shown in Table 1 below together with the results obtained by the Mohr method using an automatic titrator and a commercially available salt meter for measuring electric conductivity. The chloride concentration was represented by the weight concentration (%) of sodium chloride.

In the electric conductivity measurement salt meter, a large error is recognized in foods having a high chloride concentration, but it can be seen that the method of the present invention is in good agreement with the Mohr method, which is the official JIS method.

[Effects of the Invention] The present invention has the following effects.

(1) Since a column using a substance which undergoes a substitution reaction with chloride ions as a stationary phase is used, excellent chloride selectivity from other coexisting ion species can be expected.

(2) Since the substitution reaction type column is used, direct measurement of high concentration chloride is possible, and troublesome sample dilution and errors due to dilution can be avoided.

(3) The column is easy to handle because it is a consumable type column utilizing an apparatus reaction.

(4) When one of the substitution reaction products is insoluble, the substance remains in the column, so that resources can be recovered. For example, when a silver salt compound is used, most of the silver can be recovered as silver chloride, which can save resources.

(5) Since the substitution reaction is used, the stoichiometric relationship is clear, and the measurement method has the advantages of chemical analysis and instrumental analysis. Thus, highly accurate measurement can be easily performed.

(6) Apparatus Since a flow injection analyzer using a reaction type column is used, measurement can be performed with a small volume of sample, and a large number of samples can be analyzed in a short time, which is an excellent control analysis method. It will be a chloride measurement method.

(7) When silver chromate, silver iodate, or silver dichromate is used as a substance that undergoes a substitution reaction with chloride ion, chloride ion and silver hexacyanoferrate (III) are used as compared with silver hexacyanoferrate (III). Lower concentration (0.00
There is an advantage that it can be detected up to 1% NaCl concentration).

(8) When silver dichromate is used as a substance that undergoes a substitution reaction with chloride ions, there is an additional advantage that an acidic solution can be used as a carrier.

(9) When silver iodate or silver oxalate is used as a substance that undergoes a substitution reaction with chloride ions, a sample containing contaminants having strong absorption in the visible region can be selected by selecting a detection wavelength in the ultraviolet region. On the other hand, there is an advantage that the analysis can be performed without being affected by the influence.

(10) When mercury chloranilate is used as a substance that undergoes a substitution reaction with chloride ions, there are advantages such as being stronger against light and more stable than using a silver salt.

[Brief description of the drawings]

FIG. 1 is a block diagram of a flow injection analyzer according to an embodiment of the present invention. FIG. 2 is a sectional view of a chloride ion replacement column used in the apparatus shown in FIG. FIGS. 3 and 4 relate to the first embodiment of the present invention.
The figure shows the chromatogram, and FIG. 4 shows the absorbance with respect to the concentration of NaCl. FIGS. 5 and 6 relate to a second test example of the present embodiment.
The figure is a chromatogram, and the sixth is a diagram showing absorbance with respect to NaCl concentration. 7 and 8 relate to a third test example of the present embodiment, and FIG.
The figure shows a chromatogram, and FIG. 8 shows the reduction current with respect to the concentration of NaCl. 10: Storage tank 12: Carrier 14: Pump 16: Sample injector 18: Chloride ion exchange column 20: Detector 22: Stationary phase 24: Stainless steel tube 26: Sintered filter 28: Dispersant

Claims (4)

(57) [Claims] 1. A stationary phase containing a substance that undergoes a substitution reaction with chloride ions is loaded into a tube, filters are disposed at both ends of the tube, and fine powder substance that reacts and displaces with the chloride ions is hexacyanoiron ( III) A chloride ion-exchange column, wherein the column is any one of silver acid, silver chromate, silver iodate, silver dichromate, silver oxalate and mercury chloranilate. 2. The stationary phase according to claim 1, wherein a fine powder substance that undergoes a substitution reaction with chloride ions in a fine powder dispersant is decomposed. The filter is a sintered filter. The chloride ion-exchange column according to claim 1, wherein a fine powder is charged in the column. 3. The chloride ion according to claim 1, wherein the stationary phase has a weight ratio of the fine powder substance that undergoes a substitution reaction with chloride ion to the dispersant is 1: 3 to 5. Replacement column. 4. A mobile phase liquid sending pump, a chloride ion replacement column according to claim 1, which is connected to a downstream side of the pump, the pump and the chloride ion replacement column, A sample injector that is interposed in the flow path between and in which a sample is injected, and a detector that is connected to the downstream side of the chloride ion exchange column and detects a substitution reaction product with the chloride ion. A flow injection analyzer, comprising: