METHOD FOR QUALITATIVE AND QUANTITATIVE COLORIMETRIC DETERMINATION OF FORMALDEHYDE IN MILK Russian patent published in 2023 - IPC G01N33/04 

FIELD: dairy industry.

SUBSTANCE: invention concerns the qualitative and quantitative colorimetric determination of formaldehyde in milk. Preliminarily, denaturation and sedimentation of milk sample proteins are carried out by acidification with hydrochloric acid, heating the resulting mixture and centrifugation. The pH required for the reaction is adjusted with a sodium hydroxide solution, a mixed reagent solution is added: an aqueous solution of acetylacetone, acetic acid and ammonium acetate, and heated. Microextraction of the resulting derivative is carried out in a microvolume of molten thymol. The separation of the aqueous and organic phases is achieved by centrifugation; after that, the upper phase of the extract is taken, applied in a thin layer on a black paper substrate, and visual and/or instrumental spectrofluorimetric determination is carried out. The quantitative determination of the analyte in the sample is carried out on the basis of a pre-built calibration graph using analyte calibration solutions.

EFFECT: invention makes it possible to completely exclude the use of toxic solvents, to ensure low consumption of reagents and safe solvents, as well as high productivity and sensitivity of the determination.

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