JP2968897B2 - Method for producing precise calibration liquid, method for calibrating analyzer using the same, and apparatus for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for producing a precision calibration solution containing a trace amount of a target ion, and a method for calibrating an analyzer using the calibration solution. The present invention relates to a manufacturing apparatus and a method suitable for a site such as a factory that does not have the same.

[0002]

2. Description of the Related Art Conventionally, when performing quantitative analysis using various types of analyzers, calibration of the scales of the analyzers and creation of a calibration curve are performed using a calibration solution (also referred to as a standard solution) having a known concentration in advance. I have. When the concentration of the calibration solution is relatively high, such as about ppm, the calibration solution can be prepared relatively easily even in an on-site analysis room such as a factory that is not so equipped.
In the case of a very small concentration of the order of ppb, it is difficult to obtain dilution water (usually pure water) substantially free of target ions necessary for preparation of the calibration solution, or Due to the problem of contamination of the container, it is practically impossible to prepare a highly reliable calibration solution.

[0003] Therefore, for example, in the case of a sodium monitor for measuring the sodium concentration in the outlet water of a boiler condensate desalination device of a power plant, the sodium concentration in the outlet water is actually 0.02 ppb or less. Therefore, since a precise calibration solution containing such a trace amount of sodium ions cannot be prepared, calibration of a sodium monitor using a sodium ion-selective electrode is unavoidably performed using a calibration solution having a high concentration. In other words, the conventional sodium monitor calibration method uses (1) a standard calibration stock solution of about 1 ppm in order to make the influence of container contamination negligible.
(2) Outlet water of condensate desalination equipment (0.00
0 to 3.000 ppb sodium ion concentration)
(3) In order to make the effect of sodium in the dilution water negligible, dilute the stock solution with outlet water at a concentration of 100 p.
Stop the solution at about pb and use it as a calibration solution. (4) Calibration is performed by the following two-point calibration.

That is, as shown in FIG.
b. The output (a) of the calibration solution is stored, and then 1000 p
The output (b) in pb is stored, and then (A),
(B) Extrapolating a straight line passing through the point to 0.1 ppb or less, and measuring the concentration range of 0.1 ppb or less.

When the sodium concentration is observed by passing the outlet water of the condensate desalination apparatus to the sodium monitor which has been calibrated in such a manner, as shown in FIG. It is generally eliminated gradually and shows around 0.1 ppb after several hours. But,
When the sodium concentration in the condensate demineralizer outlet water is measured by another analyzer (for example, an atomic absorption analyzer), it is actually 0.0%.
Since the calibration method has been confirmed to be 2 ppb or less, the above calibration method has a problem, and the indicated value of the monitor is 0.1 ppb.
It turned out to be stable in the vicinity of b, and the measurement in the low concentration range was found to be inaccurate. The reason for this is that although the sodium concentration to be actually measured is in the range of 0.02 ppb or less, the
The calibration is performed at 0 to 1000 ppb, and the calibration is performed at very different concentrations.

On the other hand, if the calibration is carried out using a calibration solution having a sodium concentration of 0.02 ppb or less, the measured value can be expected to be accurate. As described above, it is usually difficult to prepare the solution in an on-site analysis room or the like, and the solution is extremely easily contaminated and cannot maintain a stable sodium concentration. Can not.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a precision calibration solution that can be easily prepared even in an on-site analysis room or the like where analysis equipment is not provided. It is an object of the present invention to provide a method for producing the same, a production apparatus for the same, and a method for calibrating an analyzer using the same.

[0008]

In order to achieve the above object, the present invention provides (A) a casing having at least an inflow hole and an outflow hole, and (B) an ion of the desired ion which is filled in the casing. A first strong cation or anion exchange resin having a calculated and free form in a ratio, and a second strong cation or anion exchange resin having a predetermined ratio of a counterion form and a free form of the desired ion. Alternatively, a mixture with a cation exchange resin, comprising the above (A) and (B), by supplying water to the inlet and passing through the mixture to discharge a precision calibration solution containing a trace amount of target ions. The apparatus for producing a precision calibration liquid is configured to be taken out from the hole.

The present invention also provides a first strong cation or anion exchange resin having a calculated ratio of an ion form and a free form of a target ion, and a counter ion form and a free form of the target ion. A method for producing a precision calibration solution for producing a precision calibration solution containing a trace amount of ions of interest by passing water through a mixture with a second strong type anion or cation exchange resin having a predetermined ratio of the shape. And a method for calibrating an analyzer using a precision calibration solution produced by the above production method.

Hereinafter, the present invention will be described in detail.

FIG. 1 shows an embodiment of an apparatus for producing a precision calibration solution according to the present invention. In FIG. 1, reference numeral 12 denotes a cylindrical casing having both ends closed. A water inlet 14 is formed at the head of the casing, and a precision calibration solution outlet 16 is formed at the bottom.

The material of the casing may be any material as long as the desired ions do not leak out. For example, a synthetic resin such as an acrylic material or a metal such as a stainless steel material is preferable.

The casing 12 contains a mixture 18 of a strongly acidic cation exchange resin and a strongly basic anion exchange resin.
Is filled between the inflow-side filter 20 and the outflow-side filter 22, and the filters 20 and 22 prevent the mixture 18 from flowing out of the casing 12 to the outside.

The resin mixture 18 comprises a first strong cation or anion exchange resin having a calculated ratio of the ionic form and the free form of the target ion of the calibration solution to be produced, and the target ion And a mixture with a second strong anion or cation exchange resin having a predetermined ratio of the counter ion form and the free form.

The desired ions are Na ⁺ , K ⁺ , Li ⁺
In the case of producing cations such as those described above and a precision calibration solution for these cations, the first ion exchange resin is a strongly acidic cation exchange resin. The ratio of the ionic form and the free form (in this case, H form) of the first ion exchange resin is represented by the following formula (1).

[0016]

(Equation 1) The following equation (2) derived from the ion exchange equilibrium equation

[0017]

(Equation 2) Is calculated by That is, [RM] and [R-
H] and the cation concentration M of the calibration solution obtained by the ratio
^q is determined.

The second ion exchange resin mixed with the first cation exchange resin is an anion exchange resin composed of a counter ion form of the cation and a free form (OH form in this case). Cl ⁻ , which is the counter ion of the cation in the liquid,
In addition to supplying anions such as SO ₄ ²⁻ , NO ₃ ^{− and the} like, the pH is always about 7 (that is, the hydrogen ion concentration is 1 × 10 ⁻⁷ e) regardless of the quality of the water flowing through the inlet 14.
(q / l) is obtained from the outlet 16.

The ratio between the counter ion form and the free form of the strongly basic anion exchange resin does not have to be strictly defined as in the case of the first cation exchange resin.
Any ratio can be used as long as a precision calibration solution of about 7 can be obtained. Generally, the equivalent% of the counter ion type is used.

[0020]

(Equation 3) Is about 0.1 to 50%.

The mixing ratio of the first cation exchange resin and the second anion exchange resin is not particularly limited, but generally, the first ion exchange resin: the second ion exchange resin = 1: 1 by volume ratio. It is preferable to set it to 1-1: 2.

On the other hand, ions are Cl of interest ^- such as a halogen or NO ₃ ^-, a anion such as SiO _2, in the first ion exchange when manufacturing precision calibration solution of these anions The resin is a strongly basic anion exchange resin. First
The ratio of the ion form and the free form (OH form) of the ion exchange resin of formula (3) is

[0023]

(Equation 4) The following equation (4) derived from the equation of ion exchange equilibrium shown by

[0024]

(Equation 5) It is calculated by That is, [R-N] and [R
Anion concentration N ^m of calibration solution obtained by the ratio of the -OH] are determined.

The second ion exchange resin mixed with the first anion exchange resin is a cation exchange resin comprising a counter ion form of the anion and a free form (in this case, H form). Na ⁺ , which is a counter ion of the anion in the liquid,
While supplying cations such as K ^+,
Regardless of the water quality, the pH is always about 7
A precise calibration solution having a hydroxyl ion concentration of 1 × 10 ⁻⁷ eq / l is obtained from the outlet 16.

The ratio between the counter ion form and the free form of the strongly acidic cation exchange resin does not have to be strictly defined as in the case of the first anion exchange resin. Any ratio can be used as long as a precise calibration solution can be obtained, but generally, the equivalent% of the counter ion type is adjusted to 0.1 to 10%.

Although the mixing ratio of the first anion exchange resin and the second cation exchange resin is not particularly limited, the same volume ratio as in the case of producing the above-mentioned cation calibration solution may be used.

Next, the first ion exchange resin and the second ion exchange resin in the ionic form and the free form having a ratio calculated by using the above formula (2) or (4) to obtain a desired ion concentration. A description will be given of a case in which water is passed through the calibration liquid manufacturing apparatus shown in FIG.

The water to be passed is not particularly limited. For example, tap water, industrial water or the like containing relatively large amounts of impurity ions may be used, but a calibration solution having a predetermined concentration can be stably produced for a long period of time. When necessary, it is preferable to use high-purity water. For example, in a power plant, it is good to use the condensate desalination unit outlet water of a boiler.

When the water is supplied to the inlet 14 of the manufacturing apparatus, the water comes into contact with the RH type cation exchange resin and the R-OH type anion exchange resin while flowing down the inside of the casing 12, and the water Is absorbed and removed to obtain pure water containing almost no impurity ions. The pure water further flows down in the casing 12, and in the process, the pure water and the cation exchange resin or the anion exchange resin in the casing 12 have the following formula (1) or (2). As a result, a precise calibration solution containing a trace amount of target ions having the concentration calculated by the equation (2) or (4) is taken out from the outflow hole 16.

The obtained precision calibration solution is the same as the above-mentioned N
a Used not only for calibration of an ion monitor, but also as a standard solution for preparing a calibration curve in ion chromatography analysis, atomic absorption analysis and the like.

[0032]

【Example】

Example 1 (Production of sodium ion calibration liquid) Hydrogen ion form 99%
(Equivalent%, hereinafter the same), 100 ml of strongly acidic cation exchange resin (trade name: Amberlite 200C) of 1% Na ion form, and 90% of hydroxyl group form and 10% of strong basic anion exchange resin (Cl ion form) (trade name) : Amberlite IRA-900) 100ml
Was used to produce the calibration liquid production apparatus for the mixed resin bed shown in FIG. The outlet water (pure water having an electrical conductivity of 0.06 μS / cm) of the condensate desalination unit of the boiler is supplied to the SV 16 through the inflow hole 14.
(3.2 l / Hr). FIG. 2 shows the result of analyzing the concentration of sodium in the precision calibration solution flowing out of the outflow hole 16 with an atomic absorption spectrometer. The sodium concentration in the precision calibration solution is 0.01 minutes after the start of the outlet water supply.
ppb and remained constant.

Here, when the sodium concentration is calculated using the above equation (2),

[0034]

(Equation 6) Since the obtained calibration solution is pure water, [H ⁺ ] = 10
^-7 (pH 7).

As described above, the calculated value (0.009 ppb) of the sodium concentration in the precision calibration solution is an actually measured value (0.01 ppb).
And showed good agreement.

(Calibration of sodium ion-selective electrode) The precision sodium calibration solution (0.01 p
pb) and a sodium ion concentration of 1.0 ppm (= 10
And a concentration of 1% by diluting this undiluted calibration solution with ultrapure water (electric conductivity, 0.06 μS / cm or less).
The sodium monitor for the outlet water of the condensate desalination apparatus of the boiler was calibrated using a 00 ppb sodium calibration solution.

The monitor was manufactured by AB Vegerius Industry Co., Ltd. using a sodium ion-selective electrode, and the electrode was housed in a flow-through measuring cell.

First, the monitor was calibrated with a 100 ppb calibration solution and then with a 1000 ppb calibration solution according to a conventional method.

Next, the outlet water of the boiler condensate desalination apparatus having an electric conductivity of 0.06 μS / cm was passed through the cell, left until the indicated value on the monitor showed 0.1 ppb, and then manufactured as described above. After passing the precision calibration solution (0.01 ppb) through the cell (25 ml / min) for 15 minutes,
Monitor was calibrated to b. Thereafter, the outlet water was passed through the cell again, and the result of monitoring the sodium concentration in the outlet water was shown in FIG.

Table 1 shows the measured value of the sodium concentration in the outlet water using an atomic absorption spectrometer (AA) and the measured value of the monitor. From Table 1, it can be seen that the monitored values of the outlet water and the values measured by the atomic absorption spectrometer agree well.

[0041]

[Table 1]

[0042]

[Table 2] Example 2 (Production of Calibration Solution for Chloride Ion) Anion exchange resin having 95% hydroxyl group and 5% Cl ion (trade name: Amberlite IRA-9)
00) Cation exchange resin of 1000 ml, 99% hydrogen ion form and 1% Na ion form (trade name: Amberlite 200C)
Using 1000 ml, the calibration liquid production apparatus of the mixed resin bed shown in FIG. 1 was produced. Ultrapure water (0.06μ
S / cm) was passed through SV16 (32 l / Hr). FIG. 4 shows the result of the actual measurement of the chloride ion concentration in the precision chloride ion calibration solution flowing out of the outlet hole 16 by using an ion chromatograph analyzer. From FIG. 4, it can be seen that a precision calibration solution having a substantially constant concentration (0.01 ppb) can be obtained in about 10 minutes after the start of water flow.

On the other hand, the calculated value of the chloride ion concentration obtained from equation (4) is

[0044]

(Equation 7) Also, [OH ^-] calibration solution obtained is pure water because pH 7 =
It is 10 ^-7 .

As described above, the chloride ion concentration in the manufactured precision calibration solution showed a good agreement with the calculated value.

[0046]

According to the present invention, an ion exchange resin is used to fill a precision calibration solution containing a trace amount of target ions, which could not be prepared in an on-site analytical room where there is no sufficient facility. It can be easily manufactured simply by passing water through the casing, and the analyzer calibrated with this precision calibration solution can accurately measure an extremely small area, which has been difficult to measure conventionally.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a precision calibration liquid manufacturing apparatus of the present invention.

FIG. 2 is a graph showing the relationship between the concentration of a calibration solution manufactured by the precision calibration solution manufacturing apparatus of the present invention and time.

FIG. 3 is a graph showing the sodium ion concentration in the outlet water of the boiler condensate demineralizer measured over time by a sodium monitor calibrated by the calibration method of the present invention.

FIG. 4 is a graph showing the change over time of the ion concentration of a precision chloride ion calibration solution manufactured by the manufacturing apparatus of the present invention.

FIG. 5 is an explanatory view showing a conventional sodium monitor calibration method.

FIG. 6 is a graph showing an output of a monitor calibrated by a conventional sodium monitor calibration method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Casing 14 Inflow hole 16 Outflow hole 18 Resin mixture 20 Filter 22 Filter

Claims (3)

(57) [Claims] (A) a casing having at least an inflow hole and an outflow hole; and (B) a first strength filled in the casing and having an ion form and a free form of a target ion at a calculated ratio. A mixture of a cation or anion exchange resin of a type and a second strong type of anion or cation exchange resin having a predetermined ratio of a counter ion form and a free form of the desired ion, (A), ( B), wherein a precise calibration solution containing a trace amount of target ions is taken out from the outflow hole by supplying water to the inflow hole and passing through the mixture. 2. A first strong cation or anion exchange resin having a calculated ratio of an ion form and a free form of a target ion, and a counter ion form and a free form of the target ion are specified. A method for producing a precision calibration solution, which comprises passing water through a mixture with a second strong-type anion or cation exchange resin having a ratio of 2 to produce a precision calibration solution containing a trace amount of target ions. 3. A method for calibrating an analyzer using a precision calibration solution produced by the production method according to claim 2.