METHOD OF DETERMINING 2,4-DINITROPHENOL AND 2-AMINO-4-NITROPHENOL WHEN BOTH ARE PRESENT IN BIOLOGICAL FLUIDS Russian patent published in 2011 - IPC G01N33/50 

FIELD: chemistry.

SUBSTANCE: biological fluid containing the analysed substances is diluted with a buffer solution with pH 10-11, treated with 2,3,5-triphenyltetrazolium, the amount of which is 0.025% of the weight of the solution, extracted once with chloroform with volume ratio of aqueous phase to organic phase equal to 1:1. The chloroform extract is separated and photometric measurements are taken. Content of 2,4-dintrophenol is calculated from the value of optical density. The aqueous phase is extracted twice with chloroform with volume ratio of aqueous phase to organic phase equal to 1:1. The chloroform extracts are discarded. The amount of 2,3,5-triphenyltetrazolium chloride in the aqueous phase is brought up to 0.6-1.0%. The aqueous phase is extracted once with chloroform with volume ratio of aqueous phase to organic phase equal to 1:1. The chloroform extract is separated and added to ethanol in amount of 25% of the volume of chloroform. The obtained solution undergoes photometering and content of 2-amino-4-nitrophenol is calculated from the value of optical density.

EFFECT: high selectivity and accuracy of analysis.

2 ex, 3 tbl