METHOD FOR DETERMINING RESIDUAL AMOUNTS OF AVILAMYCIN IN BIOLOGICAL TISSUES OF ANIMAL ORIGIN Russian patent published in 2022 - IPC G01N30/00 G01N33/02 G01N33/12 

FIELD: analytical chemistry.

SUBSTANCE: invention relates to the field of analytical chemistry and concerns a method for determining the residual content of avilamycin in biological tissues of animal origin. The method includes extraction of dichloroisoevernic acid from tissues with acetone, concentration of the resulting extract to dry, followed by hydrolysis of the residue with caustic soda, purification of the hydrolysate with ethyl acetate and its acidification with orthophosphoric acid, subsequent additional purification of the resulting solution and transfer of the determined compound to the ethyl acetate layer for further concentration and re-dissolution before analysis by high-performance liquid chromatography in combination with tandem mass spectrometry (HPLC-MS/MS). At the same time, the acetone : sample weight ratio is observed during extraction, equal to 5 cm³ of acetone per 2 g of sample weight, the hydrolysate is cleaned once before acidification using 3-5 cm³ of ethyl acetate, and the acidified hydrolysate is additionally purified with 3-4 cm³ of hexane with further removal of the organic layer and the addition of ethyl acetate, stirring on a shaker and centrifugation. Then the ethyl acetate layer is evaporated dry in the nitrogen current, re-dissolved in 1 cm³ of 0.5% formic acid and analyzed by HPLC-MS /MS.

EFFECT: method provides for a 30% increase in the analytical response of the detector signal for the avilamycin metabolite, which makes it possible to confidently work with complex types of samples as a result of reducing the influence of baseline noise; significantly reduce the consumption of acetone during extraction; simplify the procedure of liquid-liquid extraction with ethyl acetate; avoid the solid-phase purification procedure (SPP).

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