JPS59163557A - Potential difference detector - Google Patents

Abstract

PURPOSE:To detect with high accuracy a univalent cation, namely, an alkali metallic ion and an ammonium ion by combining an ion electrode containing a neutral carrier as an induction object, and a reference electrode. CONSTITUTION:A neutral carrier which is useful as a sensitive material is cyclic peptide, cyclic polyether, or nactine, etc. An ion electrode is a polymer mixed film electrode, namely, a covered wire electrode, and consists of a metallic wire 1, a tube 2 of polyvinyl chloride, and a sensitive film 3 formed on the tip of the metallic wire 1. An ion electrode 15 and a reference electrode 8 are incorporated in a potential difference detector. For example, the reference electrode 8 silver - silver chloride electrode containing saturated KCl, measures EMF (mV) generated between two electrodes by a pH/mV meter, and records its variation in a recorder in the shape of an ion chromatograph.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a potential difference detector, and more specifically:
The present invention relates to a potentiometric detector for detecting monovalent cations using an ion-selective electrode, which is useful in ion separation devices such as high-speed ion chromatographs.

As is well known, an ion-selective electrode (also simply referred to as an ion electrode, hereinafter referred to as such) responds selectively to the ions that are the object of analysis, and changes the concentration of the ions. Ion electrodeposition belongs to the membrane chamber $1 and uses a membrane that is sensitive only to specific ions, a so-called sensitive membrane, or something similar.In recent years, such ion There has been a remarkable amount of research into Ti, and a large number of electrodes, including the glass electrode that was developed early on, have been developed and are now commercially available.By using these electrodes, it is possible to collect various ions and gases. It is possible to perform direct and rapid measurements without complicated operations such as extraction, reaction, and color development.Ion electrodes are therefore useful for analytical chemistry in industrial processes, food, medicine, the environment, basic research, etc. It is widely used in the field of

In view of the above-mentioned advantages, attempts have been made to use ion electrodes together with ion separation devices, such as ion exchange columns for ion chromatography. However, this attempt has only led to useful results in the detection of halide ions and anions.

An object of the present invention is to provide a potential difference detector that can detect monovalent cations, that is, alkali metal ions and ammonium ions with high precision when used in conjunction with an ion chromatograph.

As a result of repeated research to achieve the above object, the present inventors have found that it is effective to use a combination of an ion electrode containing a 211 tral carrier as a sensitizer and a reference electrode in a potential difference detector. I just discovered this.

Examples of 211 tral carriers useful as sensitizers in the practice of the present invention include: (1) cyclic zotides such as palinomycin, and (2) cyclic polyethers (crown ethers) such as benzene. [15] Crown-5, etc. (3) Tictins nonactin, monactin, dinactin, trinactin,
For example, an ion electrode illustrated in FIG. 1 is manufactured using a sensitive material such as tetranactin as described above. This electrode is made of polymer (
pvc) A mixed membrane electrode, that is, a U-ray receiving electrode, consisting of gold, metal wire 1, and polyvinyl chloride (PVC) chive 2.
, and a metal wire].

For example, bend the tip of the platinum wire to cover the PVC chip. Separately, PVC as a polymer material is dissolved in tetrahydrofuran (THF) to obtain a THF solution of PvC. The reactant is dissolved in a membrane solvent (DEH8), and the previously prepared PVC solution is added thereto to prepare a mixed solution. Cover the tip of the platinum wire with this mixed solution until the exposed portion is completely covered. The coating is then dried at room temperature for several days to evaporate the THF and obtain an ion electrode with the desired sensitive membrane. This electrode should be
It is immersed in pure water for 0 to 60 minutes to obtain a constant electrode potential before use.

If necessary, an ion electrode having the structure shown in FIG. 2 can also be manufactured. First, the tip of the glass tube 4 is sealed with a suitable porous material 5, and a sensitive liquid 6 consisting of a sensitive substance and a solvent is held therein. The metal wire 7 is immersed in the sensitive liquid.

The ion electrode and reference electrode manufactured as described above are assembled into a potential difference detector. A preferred configuration example of the potential difference detector according to the present invention is as illustrated in FIG.

The potential difference detector exemplified here has two
4 solid Teflon ■ three-way valve (mini-cheer joint) 1
0 is used as the cell block of the detector. three-way valve 10
The components other than the following are summarized below: (8) Reference electrode body; (9) O-! Made of J song silicone rubber): Made of alpha Teflon A? Separation; Oa silicone rubber tube; 0) Teflon ■ tube: α→Separation column outlet; α→Ion rod body: and αQ PVC (as a binder). Eluent flows from arrow A to arrow B.

Production example: An ion electrode having the structure shown in FIG. 1 was manufactured.

The metal wire is a platinum wire, and the composition of the sensitive film is THF
After evaporation, the reactant was 3 parts by weight, DEH 870 parts by weight, and PVC 27 parts by weight. As the sensitizer in this example,
Palinomycin, benzo[15]crown-5, nonactin, and tetranactin were used. Tetranactin alone was 90 parts, and also contained a mixture of G and trinactin 5 parts. The reference electrode was a silver-silver chloride electrode' containing saturated KC1. The cell capacity between the electrodes was approximately 50 μL. The EMF (mV) generated between two electrodes was measured with a pH/mV meter, and the change was recorded on a recorder in the form of an ion chromatograph.

Furthermore, a high-speed ion chromatography apparatus was constructed from a pump, a sample injector, a cation separation column, and the above-described potentiometric detector of the present invention. Prepared by using nitric acid and high purity deionized water as an eluent.
An acidic solution of

Example 1: Five alkali metal ions (NaNH4,
An equal concentration mixed solution of RtzCs) was injected as a sample. Each sample (introduced amount 100 μt) was 5×1
Contained 0 moles of metal ions. Representative ion chromatograms obtained from each detector using palinomycin, benzo[151 crown-5, nonactin, and tetranactin] are shown in Figures 4, 5, 6, and 7, respectively. show. Since nitric acid with a pH of approximately 2.5 is used as the eluent, the electrodes of these sensitizers are both H+
It was selected because it has good selectivity for. Therefore, the sensitivity of a potentiometric detector is determined by the selectivity between H ions and detected ions, and the magnitude of the response peak for each ion is similar to the selectivity when using these ion electrodes in the patch method. be.

As can be understood from the ion chromatograms in Figures 4 to 7, the cod in the potentiometric detector using palinomycin,
The response to 12b+ and the response to NI (4+) of a potentiometric detector using nonactin and tetranactin is large, and these ions are approximately 1xl with introduction of 100 μt.
Ions up to F7M were detected. However, the upper limit was approximately 1 × 10 M, depending on the column resolution.

Note that the content ratio of Na+, NH4+, and Ni+ in serum and urine is opposite to the sensitivity ratio for these ions of a potentiometric detector using nonactin or tetranactin, so these ions cannot be quantified simultaneously. This will be explained in Example 2 below.

Example 2: Serum and urine were injected as samples into the high-speed ion chromatography device manufactured in the above manufacturing example at an amount of 5 μt and 0.5 μt, respectively. The potentiometer on the water side used an ion electrode with tetranactin as the sensitizer. Figure 8 (
Ion chromatograms as shown in FIG. 9 (for serum) and FIG. 9 (for urine) were obtained. Furthermore, when the experiment was repeated, serum was 2-5 μt, urine was 0.1-0.5 μt.
It was found that by direct introduction of t, three types of ions, Na+, NH4+rK+, could be quantified with an accuracy within 2 coefficients.

As can be understood from the above, when the potentiometric detector of the present invention is used, monovalent cations, especially alkali metal ions and ammonium ions, contained in samples to be analyzed such as serum, urine, rainwater, and non-biological materials can be detected. It can be detected with high precision and has good reproducibility. According to the present invention, among other things, several ions can be quantified simultaneously.
y).

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing one configuration example of an ion electrode useful for implementing the present invention, and FIG. 2 is a schematic cross-sectional view showing another configuration example of an ion electrode useful for implementing the present invention. 3 is an explanatory diagram showing a preferred example of the potentiometric detector according to the present invention, and FIG. 4 is an ion chromatogram of monovalent cations obtained with a potentiometric detector using a palinomycin electrode. , Figure 5 is an ion chromatogram of valent cations obtained with a potentiometric detector using a benzo[15]crown-5 electrode, and Figure 6 is an ion chromatogram of monovalent cations obtained with a potentiometric detector using a nonactin electrode. Figure 7 shows the ion chromatogram of monovalent cations obtained with a potentiometric detector using a tetranactin electrode. Figure 8 shows the ion chromatogram of serum obtained with a potentiometric detector using a tetranactin electrode. FIG. 9 is an ion chromatogram of urine obtained with a potentiometric detector using a tetranactin electrode. In the figure, 1 is a metal wire, 3 is a sensitive membrane, 5 is a porous material, 6 is a sensitive liquid, 7 is a metal wire, 8 is a reference electrode, and 15 is an ion electrode. Patent applicant Tsune Shirai Takashi Yusuzu Showa Denko Co., Ltd. Patent agent patent attorney Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney 1) Yukio Patent attorney Akiyuki Yamaguchi Figure 1 Figure 2 Figure 3 Figure 5 1 Figure 6 Figure 7 NH4'' Figure 8 Between 1 and j (mtn) Figure 9 Between bow and 5 (min, )

Claims (1)

[Claims] 1. A phase difference detector for detecting monovalent cations, which comprises a combination of an ion-selective electrode containing a 211 tral carrier as a sensitive material and a reference electrode.