SU997385A1 - Standard for atomic-absoption determining of arsenic in organic medium - Google Patents

Abstract

Use of tetraphenylarsonium perrhenate as a standard for the atomic absorption determination of arsenic in organic media.

Description

The invention relates to the field of spectral analysis of substances in organic media, in particular atomic absorption analysis of substances, and can be used in enterprises that have atomic absorption equipment for determining mice. ka

Atomic absorption analysis is a relative method of determination that requires preparation of a standard before each determination. The latter is usually prepared by extracting known quantities of the mouse from the aqueous solution with any of the extrat. TOB.

Substances that are used as standards in the atomic absorption analysis of organic media must meet the following conditions: the main substance of the standard

It should be easily determined by any method with high accuracy, its content should not change during storage, they should be dissolved in organic solvents and their solutions should be stable. It is also desirable that the main substance and standard solutions should be low in CJ 00 sichny, free of odor and stored in ordinary dishes.

ate

It is known to use as standards for the atoMHci-absorption determination of arsenic in organic media of oils with a known arsenic content, as well as inorganic salts, for example, Na2.HAs04 As409. However, the primary definition of a mouse in oil with high accuracy is difficult, and these standards can only be applied when analyzing the same oils, but it is impossible to analyze extracts, and the use of inorganic salts does not give reproducible results. Moreover, solutions in organic solvents are not stable. It is also known to use as a standard for the atomic absorption determination of arsenal in triphenylarsine organic media. A disadvantage of the known standard is the possibility of oxygen oxidation of the air during long-term storage, which can lead to changes in the content of the basic substance of the standard, the relative toxicity of the standard, and the difficulty of accurately determining the mouse in the standard. Solutions of triphenyl arsin (TFA) in organic solvents are not stable in long glass storage (over 3 months) in a glass container; The aim of the invention is to increase the stability of the standard and its solutions 8 organic solvents, as well as to reduce toxicity and simplify the procedure for preparing the standard and its solutions. This goal is achieved by using as a standard for the atomic absorption determination of arsenic tetraphenyl arsonium perpenate (TFAP) and an organic alcohol of the formula, where R is C.2 - Cg. A new (first) prescription of this compound is proposed, which is obtained by precipitation from an aqueous solution of potassium perrhenate with tetraphenylarsonium chloride. The precipitate is filtered off dried. Under these conditions, a substance with a known arsenic content is obtained; therefore, it is not necessary to carry out additional analysis per mouse. To prepare a solution with a known mouse content, it suffices to know the weight of the substance. The conversion factor per mouse to is equal to 0.1183. The resulting TFAP is a white crystalline powder, odorless, low toxic, stable in time and to the action of atmospheric oxygen. To prepare TFAP solutions, an aliphatic alcohol with CgCg radicals, Example P1, is used. Preparation of rasters for the construction of calibration raffies. Solution 1. A weighed portion of 0, g. TFAP is placed in a 50 ml volumetric flask, 20 ml of ethyl alcohol is added, heated on a water bath to dissolve the weighed portion. Then 20 ml of ethyl alcohol is added, the flask is cooled to room temperature and the volume is made up to the mark. The solution contains 100 µg / ml As and is used as standard. Solution 2. A portion of 0, g. TFAP is placed in a 100 ml volumetric flask, 25 ml of isopropyl alcohol is added. After dissolving the batch, make up to the mark with o-xylene. The solution contains 20 µg / ml As and is used as standard. Solution 3. A weighed amount of 0, g. TFAP was placed in a 50 ml volumetric flask, 2.3 ml of ethyl alcohol was added, heated on a water bath for 15–20 minutes, 25 ml of methyl isobutyl ketone (MIBK) were added. After dissolution of the sample, another 15 ml of MIBK is added, the flask is cooled to room temperature and the volume is adjusted to the MIBK mark: The solution contains 0 µg / ml As and is used as standard. Solution. A weighed amount of 0 g of TFAP was placed in a 100 ml volumetric flask, 5 ml of n-butyl alcohol was added, heated on a water bath for 15-20 minutes. 50 ml of MIBK are added and heated until the suspension is completely dissolved. Cool the flask to room temperature and bring the volume to the mark. The solution contains 20 µg / ml As and is used as standard. Solution 5. A weighed portion of 0, g of TFAP was placed in a 50 ml volumetric flask, 2.5 ml of ethyl alcohol was added, heated on a water bath. 25 ml of a 0.1 M solution of dirctyltin dinitrate (DNDOO) in MIBK are added and heated on a water bath until the suspension is completely dissolved. Cool the flask to room temperature and bring the volume to the mark. The mouse content in the solution is 40 µg / ml. The resulting solutions are stable for at least t months and can be stored in ordinary glassware. These solutions are used to construct calibration curves. The following are examples of hail use.

Claims (2)

The invention relates to the field of spectral analysis of substances in organic media, in particular atomic absorption analysis of substances, and can find application in enterprises: having atomic absorption equipment for determining mouse-. ka. Atomic absorption analysis is a relative determination method, requiring the preparation of a standard before each determination. The latter is usually prepared by extraction of known amounts of arsenic from an aqueous solution by any of the extractants. The substances that are used as standards in the atomic absorption analysis of organic media must meet the following requirements: the basic substance of the standard must be easily determined by any method with high accuracy, its content must not be changed during storage, they must be soluble in organic solvents and their solutions are stable. It is also desirable that the basic substance and standard solutions be low-toxic, odorless and stored! in ordinary dishes. '*' It is known to use as standards for the atomic absorption determination of arsenic in organic media of oils with a known content of arsenic, as well as inorganic salts, for example, Na _£ HAsO ₄ * As ₂ 0 ₉ . However, the initial determination of arsenic in oil is difficult with high accuracy, and these standards can only be used in the analysis of the same oils, but not in the case of extract analysis SU <"997385 A1 3 '997385' tov, and the use of inorganic salts does not produce reproducible results. Moreover, solutions in organic solvents are unstable. It is also known to use triphenylarsine as the standard for atomic absorption determination of arsenic in organic media. The disadvantage of this standard is the possibility of oxidation by atmospheric oxygen during long-term storage? which can lead to a change in the content of the basic substance of the standard, the relative toxicity of the standard, as well as difficulties in accurately determining arsenic in the standard. Solutions of triphenylarsine (TFA) in organic solvents during long-term storage (more than 3 months) in glassware are not stable; The aim of the invention is to increase the stability of the standard and its solutions in organic solvents, as well as reducing toxicity and simplifying the preparation of the standard and its solutions. This goal is achieved by using tetrafenilarsonium perrenate (TFAP) and an organic alcohol of the formula as a standard for atomic absorption determination of arsenic RHgCOH, where R - C £ - C ₈ . A new (first) purpose of the indicated compound is expected, which is obtained by precipitation from an aqueous solution of potassium perrenate with tetraphenylarsonium chloride. The precipitate was filtered off and dried. Under these conditions, a substance with a known arsenic content is obtained, therefore, additional analysis for arsenic is not necessary. To prepare a solution with a known arsenic content, it is enough to know the weight of the substance. The conversion factor for arsenic is 0.1183 · The obtained TFAP is a white crystalline powder, odorless, low toxicity, stable in time and against the action of atmospheric oxygen.