METHOD OF DETERMINING BENZOIC ACID IN WATER Russian patent published in 2014 - IPC G01N30/04 G01N21/78 

FIELD: chemistry.

SUBSTANCE: invention relates to analytical chemistry, particularly to methods of determining benzoic acid, and describes a method for quantitative determination of benzoic acid from a methyl derivative thereof - methyl ether in aqueous matrices with determination sensitivity of 5.0·10^-5 mg/cm³ with determination error of not more than 25%. The method is characterised by that quantitative determination of benzoic acid is carried out using a chromatographic method with flame-ionisation detection and includes the following steps: extraction concentration of an analyte with benzene in water samples acidified with 25% sulphuric acid solution to pH 1-3 while adding sodium chloride until a saturated solution is obtained, conducting a benzoic acid methylation reaction with diazomethane to obtain a derivative - methyl ether of benzoic acid and determining the formed methyl ether of benzoic acid by a chromatographic method with flame-ionisation detection.

EFFECT: method provides high sensitivity, selectivity and easy implementation during quantitative determination of benzoic acid in aqueous media and enables use thereof in practice in factory analytical laboratories, central laboratories of chemical companies and chemical-toxicology laboratories.

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