JPH06249775A - Monovalent copper analysis - Google Patents

Abstract

PURPOSE:To provide a method wherein monovalent copper is analyzed by a simple method without being oxidized. CONSTITUTION:In the alcohol solution of neocuproine or bathocuproine, monovalent copper preferentially forms a complex with the neocuproine or the bathocuproine even under the air, and the complex which has once been formed exists comparatively stably. Consequently, a solution which contains the monovalent copper is injected into the alcohol solution of the neocuproine or the bathocuproine, the complex with the monovalent copper and the neocuproine or the bathocuproine is formed, and the solution containing the complex is extinction-analyzed. When bivalent copper coexists in a measuring solution, there is a fear that the bivalent copper disturbs the color formation of the monovalent copper. As a result, it is preferable that a substance which forms a complex with the bivalent copper such as histidine, histamine, EDTA or the like is added as the masking agent of the bivalent copper.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to I contained in a solution.
It relates to a method of analyzing copper for value.

[0002]

2. Description of the Related Art When I-valent copper contained in a solution is to be analyzed, for example, it reacts specifically with I-valent copper to form an orange-colored complex with neocuproine or bathocuproine to form an organic solvent. A method in which the extracted substance is analyzed by absorption with a spectrophotometer can be considered.

[0003]

However, since I-valent copper is easily oxidized to II-valent copper when exposed to the atmosphere, in the extraction operation, the operation of the separating funnel to prevent contact with oxygen is carried out. Since it needs to be performed in an inert gas, special equipment is required, and the operation becomes very complicated.
Analyzing the value of copper has not been established as a general method.

An object of the present invention is to provide a method for analyzing I-valent copper by a simple method without oxidation.

[0005]

To achieve the above object, the method of the present invention comprises the steps of injecting a solution containing copper having an I value into an alcohol solution of neocuproine or bathocuproin.
It is characterized in that a complex of high-valent copper and neocuproine or bathocuproin is formed and the solution containing the complex is subjected to absorption spectrometry.

[0006]

The present inventors have found that in an alcoholic solution of neocuproine or bathocuproine, copper having an I value preferentially forms a complex with neocuproine or bathocuproine even in the atmosphere, and that the complex once formed exists relatively stably. Found.

This finding was obtained in an experiment in which copper II-valent was reduced with hydroxylammonium chloride in an ethanol solution of bathocuproin and measured by a spectrophotometer. According to the experiment, II-valent copper and hydroxylammonium chloride react quantitatively at a ratio of 2: 1 to reduce the II-valent copper to I-valent copper, and the reduced I-valent copper forms a complex with bathocuproine. Although it forms and develops color, its value shows almost no change when measured over time, indicating that it is not reoxidized.

Therefore, if the sample to be measured is sampled with a dispenser and injected into the ethanol solution of bathocuproin, the copper with I value in the sample can be measured without being affected by oxidation. Similar results were obtained with neocuproine, which reacts specifically with copper having an I value as with bathocuproin.

By the way, when II-value copper coexists in the measurement solution, the II-value copper may interfere with the color development of the I-value copper. To suppress this, it is advisable to add a substance that forms a complex with II-valent copper, such as histidine, histamine, or EDTA, as a mask agent for II-valent copper.

[0010]

【Example】

Experiment No. 1 ... Metallic copper (1 g) was dissolved in nitric acid (20 ml), water (1 l) having a constant volume of 25 ml was sampled with a whole pipette, perchloric acid (10 ml) was added, and the mixture was heated to dryness. A 250 ppm solution of II valent copper was prepared. From this, 100 μl was taken with a micropipette and 0.05% bathocuproin-ethanol solution 8
6 samples were prepared by adding 6 ml to each of 0,3.42,6.84,13.
6, 27.4 and 54.7 ppm aqueous solutions were added in 1 ml portions (these hydroxylammonium chlorides were used in molar ratios of 0, 0.125, 0.25, 0.
5, 1 and 2). Further, add 100 μl of 3 g / l histidine aqueous solution, and add 1.0 m of ethanol.
Absorbance at a wavelength of 470 nm was measured by a spectrophotometer with a constant volume. Absorbance is 0.01, 0.16, 0.29,
It was 0.54, 0.55, and 0.55. From this experiment
It can be seen that the II-valent copper reacts quantitatively with hydroxylammonium chloride and the reduced I-valent copper quantitatively forms a complex with bathocuproine.

Experiment No. 2. Prepare 5 samples of 9 ml of a 0.05% bathocuproin-ethanol solution, 0 for each,
100 μl of 0.61, 1.22, 3.05, and 6.11 g / l histidine solutions were added, and the experiment No. 100 μ from a 250 ppm solution of the same II-valued copper as that prepared in 1.
After the addition of 1 liter, the volume was adjusted to 10 ml with ethanol (these histidines were used in a molar ratio of 0, 1,
2,5,10 times), wavelength 470 with spectrophotometer
The absorbance at nm was measured. Absorbance is 0.056,
It was 0.022, 0.014, 0.005, and 0.005. From these results, it can be seen that in order to expect a masking effect, it is sufficient to add more than the equimolar amount of II-valent copper.

[0012]

According to the present invention, I-valent copper can be analyzed by a simple method without being oxidized.

Claims (2)

[Claims] 1. A method for analyzing I-valent copper, which comprises injecting a solution containing copper having I-valence into an alcohol solution of neocuproine or bathocuproine and analyzing the resulting complex solution by absorptiometry. 2. The method for analyzing I-valent copper according to claim 1, wherein a substance that forms a complex with II-valent copper, such as histidine, histamine, and EDTA, is added to the complex solution and the absorption is analyzed. .