METHOD OF QUANTITATIVE DETERMINATION OF O-, M- OR P-AMINOBENZOIC ACID Russian patent published in 1994 - IPC

FIELD: analytical chemistry. SUBSTANCE: method is based on the reaction formation of triple complex after addition of p-dimethylaminocinnamic aldehyde solution and sulfanol to aminobenzoic acid. Reaction is carried out in citrate buffer solution at pH 2.0-4.0. Solution of p-dimethylaminocinnamic aldehyde is added to specimen solution up to the concentration 4,56·10^-5-4,56·10^-4. Bright-red colored solution obtained in analyzed by photometry at maximum wavelength absorption at the range 520-540 nm. Method ensures to determine selectively one of aminobenzoic isomer in the mixture with other amines. EFFECT: improved method of assay. 4 tbl