JPS60169764A - Measurement of ion speed using ion chromatography - Google Patents

Abstract

PURPOSE:To enable the measurement of ion concn. from the relation of a peak area value by moisture and the injection amount of a standard solution, and that of the peak area value of each ion seed and the ion amount thereof. CONSTITUTION:When a pump 2 is driven, the eluate of a tank 1a is flowed through a flowline of pump 2 damper 4 connection ports 3a, 3b pre-column 5 separation column 6 detector 7 waste solution tank 1b. Next, a standard solution is injected from a connection port 3d and, when an injector 3 is turned ON, an internal flowline is changed over from the solid line to the broken line and the eluate through the damper 4 flows a flowline of connection ports 3a, 3f metering pipe 3g connection ports 3c, 3b pre-column 5 while the standard solution in the pipe 3g is fed in the pre-column 5 by the eluate and receives predetermined signal processing by on integrator 8 to obtain a chromatogram and an integrated value. Herein, the injection amount of a specimen to be measured (standard solution) can be known from the proportional relation between the injection amount of the standard solution and a water dip area value while the ion amount of each ion can be known from the proportional relation between each ion amount and a peak area value. Hereupon, the concn. of an ion speed is obtained from the quotient (W/V) of the injection amount V of the specimen to the measured and the ion amount W of the ion speed to be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a method for measuring ion concentration that can simultaneously measure the amount of a sample collected in ion chromatography and the ion concentration in a sample amount.

[Prior art]

There are two methods for collecting samples in ion chromatography: one method is to drive an injector with a measuring tube to inject a fixed amount of sample into the mobile phase (eluent), and the other is to use a microsyringe etc. to pump a roughly fixed amount of sample into the mobile phase. There is a method of injecting it inside. In the former case, a so-called absolute calibration curve method is often adopted, in which a chromatogram is created using a standard solution (or standard gas) and a sample to be measured, and the ion concentration is calculated. In the latter case, a so-called internal standard method is often adopted in which a certain amount of an internal standard substance is added to the sample to be measured and then the ion concentration in the chromate is measured.

However, when the above-mentioned absolute calibration curve method is adopted, there is a drawback that it is generally difficult to adjust the size of the peak of the chromatogram in accordance with the ion concentration in the sample. This is because although the magnitude of the peak is proportional to the volume within the metering tube of the injector, it is generally difficult to increase or decrease the volume within the metering tube.

Furthermore, when the internal standard method described above is adopted, there is a drawback that a troublesome operation of accurately adding the internal standard substance to the sample to be measured is required. This is because the internal standard substance must be different from the ion species present in the sample to be measured and must be completely separated from these ion species on the chromatogram.

[Object of the Invention] The present invention has been made in view of the above drawbacks, and its purpose is to reduce the amount of a sample collected without accurately weighing the sample to be measured and the ion concentration in this sample. It is an object of the present invention to provide a method for measuring ion species that can simultaneously measure ion species.

[Summary of the invention]

A feature of the present invention is that in a method for measuring ion species in a sample to be measured using ion chromatography, a standard solution containing the same ion species as the ion species to be measured and water is used to detect peaks due to moisture in advance. A first graph showing the relationship between the area value and the amount of standard solution injected, and a second graph showing the relationship between the peak area value of the various ion species and the ion amount are created, and then, using the sample to be measured, From the respective area values of the moisture peak and each ion peak in the obtained chromatogram and the first and second graphs, determine the injection amount V of the sample to be measured and the ion amount of the ion species to be measured, and calculate these values. The reason is that the concentration of the ion species to be measured is calculated from the quotient (Wl/V).

〔Example〕

Hereinafter, the present invention will be explained in detail using the drawings. 1st
The figure is an explanatory diagram of the configuration of an embodiment of the present invention. In the figure, la is a tank in which an eluent containing, for example, 11 N O at a concentration of 5 mM is stored, and 2 is a tank of, for example, a 1-lunger type (or diaphragm type). The pump 3 is a pump for pumping the eluent, such as a syringe type or syringe type, and has, for example, first to sixth connection ports 3 & ~ 3f and a metering tube 3g, and the solid line connection state and the broken line in Fig. 1 are connected. an injector whose connected state is alternately switched; 4 is a damper that prevents pulsation of the eluent; 5 and 6;
are a precolumn and a separation column filled with a cation exchanger with a low ion exchange capacity, 7 is a detector made of, for example, a conductivity detector, and 8 is an integrator that receives the detection signal from the detection 1i and 7 and processes the signal. , 9 is the precolumn 5. A constant temperature bath that houses the separation column 6 and the detector 7 and keeps them at a predetermined temperature (for example, jOll:) is a waste liquid tank that houses the liquid discharged from the detector 7. still,
The internal volume of the measuring tube 3g is usually 2 mL (also 2 mt in the embodiment shown in FIG. 1), but is not limited to this, and may be, for example, 10 mt or 20 mt.

The operation of the embodiment of the present invention having the above configuration will be described below. In FIG. 1, when pump 2 is driven, tank l
The eluent in a is pump 2 → damper 4 → first and second connection ports 3a, 3b of injector 3 → pre-force ram 5 →
The flow path is from the separation column 6 to the detector 7 to the waste liquid tank 1b.

Also, Li+αtPpm.

N-α5ppm, NH4+α5ppm* and Ni+
A solution containing 1 ppm (hereinafter referred to as "standard solution") was
Accurately measure 0 μt using a microsyringe, and inject it into the measuring tube 3g from the fourth connection port 3d of the injector 3.

When the injector 3 is turned on in this state, the internal flow path of the injector 3 switches from the solid line state in FIG. 1 to the broken line state. Therefore, the eluent passing through the damper 4 is
It flows in the flow path of the first connection port 3a of the injector 3→sixth connection port 3f→metering tube 3g−+sixth connection port 3C→second connection port 3b→precolumn 5.

Therefore, the above standard solution injected into the measuring tube 3g is
The eluent is carried into the precolumn 5.

The ionic species contained in this standard solution undergo predetermined separation in the precolumn 5 and the separation column 6, and then reach the detector 7, where its conductivity is detected. The detection signal output from the detector 7 is led to an integrator 8 and subjected to predetermined signal processing to provide a romatogram, an integral value, etc. as shown in FIG. Next, add 1,000μ of the above standard solution.
By accurately measuring t with a microsyringe, injecting it into the injector 3, and performing the same operation, a romatogram, an integral value, etc. as shown in FIG. 3 are obtained.

In FIGS. 2 and 3, each peak in the chromatogram appears in the direction of decreasing conductivity, and the first peak is a peak due to moisture (so-called water dip). This quarter dip often becomes saturated as the amount of standard solution injected increases. Additionally, the absolute value of conductivity, which indicates the baseline of the chromatogram, is approximately 2400 μS/ls.
It is. Similarly, the above standard solution is IDOpl,
Chromatograms, integral values, etc. are obtained for each case of 500 pj and 2000 μt. Based on the integral value etc. obtained in this way, the relationship between the amount of standard solution injected into the injector 3 (μt) and the area value of water dip (one area count is 0.125μ·see) Figure 4 is obtained by plotting. From this Figure 4, it can be seen that there is a proportional relationship between the standard solution injection amount and the water dip area value, and if the sample injection amount (standard solution injection amount) is V and the water dip area value is AWd. , the following formula (1) holds true.

V ” 4.9X10-' XA ad ・・・・・・・・・
...(1) On the other hand, from the chromatograms etc. obtained as shown in Figures 2 and 6, 1g+, NH4+, N&+
When the peak area values for each ion amount (ng) are plotted for , and +, FIG. 5 is obtained. From this Figure 5, the amount of each of the above ions (ng) and the peak area value (1
It can be seen that there is a proportional relationship between the area count α125 μV-see). Also, J”, NH4+, N
The ion amounts of a0 and K are WL, i+, and WNH, respectively.
4+, WNjL+, and WK+, LI+, N
The peak area values of H, +, Na+, and Ni
L, +, ANH4+-ANa'' and AX+, the following equations (2) to (5) are derived from FIG.

WL 1+=2.44 X j CI X AL l+
・・・・・・・・・(2) WNa+=8.13X10
XANIL+ −−−−−−−131WNH4+=
6.71X10 XANH4+ ・・・・・・・・・(
4) ” ” 'L 49 X I Q-' ×A K+
(5) Therefore, if we create a romatodalum etc. for the sample to be measured as shown in Figures 2 and 3, we can calculate the area value of the water dip and the above +11
The injection amount of the sample to be measured can be determined from the formula (ie, FIG. 2). Further, the ion amount of each ion can be known from the peak area value of each ion in this chromatogram etc. and the above-mentioned formulas (2) to (5) (ie, FIG. 6). Furthermore, the value (quotient) obtained by dividing each of the above equations (2) 2 to (5) by the above equation (1) is the ion concentration Cng/μ1 of each ion.
=ppn+). Therefore, L,”, N +,
NH4+.

and CL i + for each ion concentration value of cod ions.

When CN, L+·CNH4+, and CK+ are represented, the following equations (6) to (9) are established, and the concentration of each ion in the sample to be measured can be easily determined from these equations.

According to the embodiment of the present invention as described in detail above, the injection amount of the sample to be measured is determined from the water dip area value, and the ion amount of each ion is determined from the peak area value of each ion. This method has the advantage that the amount of a sample taken and the ion concentration in the sample can be measured without accurately weighing the sample to be measured. In addition, the conventional so-called concentration column method, which is used to concentrate the ion species to be measured when the ion concentration of the sample to be measured is low, requires the complicated process of precisely injecting a certain amount of sample into the concentration column. However, according to the present invention, it is possible to simplify the operation by injecting the sample to be measured in the approximate amount to be injected into the concentration column. Furthermore, in the conventional concentration column method described above, some ion species were generated that were not completely captured by the concentration column due to the matrix of the ion species to be measured, but according to the present invention, the ion species to be measured in the injected sample were Since all the fields are transported to the pre-column etc., there is also the advantage that the measurement error of the ion beam to be measured is significantly reduced.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the configuration of an embodiment of the present invention, Figs.
The figure shows the chromatogram created using the standard solution, Figure 4 shows the relationship between the amount of the standard solution injected and the area value of the quarter dip beak, and Figure 5 shows the amount of each ion contained in the standard solution. It is a figure which shows the relationship between and a peak area value. Ia, lb... Cypress, 2... Pump, 3... Injector, 4... Damper, 5... Precolumn, 6...
...Separation column, 7...Detector, 8...Integrator, 9...Thermostat 0 Fig. 2 M5 ion amount] n91

Claims (3)

[Claims] (1) In a method of measuring ion species in a sample to be measured using ion chromatography, using a standard solution containing the same various ion species and water as the ion species to be measured,
A first graph showing the relationship between the area value of the peak due to moisture and the amount of standard solution injected, and a second graph showing the relationship between the peak area value of the various ion species and the amount of ions are created in advance, and then, Create a chromatogram using the sample to be measured, obtain the area value of the water peak on the chromatogram and the injection amount V of the sample to be measured from the first graph, and calculate the area of each ion peak on the chromatogram. The ion amount W1 of each ion species to be measured contained in the sample to be measured is obtained from the value and the second graph, and the quotient (Wi/v
), the concentration of the ion species to be measured is determined from the following. (2) The ion species measuring method according to claim (1), wherein the moisture peak is a water dip. (3) Each of the ion species to be measured is Ll'', N@+,
NH4" and each ion of cod.