METHOD FOR DETECTING HUMAN ENDOGENOUS BLOOD PLASMA STEROIDS Russian patent published in 2012 - IPC G01N30/72 

FIELD: medicine.

SUBSTANCE: method for detecting human endogenous blood plasma steroids involves preparing solutions of reference substances in an organic solvent, preparing an analysed sample by extraction. Then the extract is boiled out, and a solid residue is dissolved in a mobile phase. It is followed by chromatographic fractionation and mass spectrometry of the reference solutions and the analysed sample. The measured results are recorded and analysed for the presence of endogenous steroids. The process of sample preparation involves extraction of the analysed blood plasma sample. The extract is divided on two aliquots one of which is modified by hydroxyamine in an acid medium and another one - by an anhydride agent presented in the form of a solution of 4-dimethylaminopyridine, triethylamine and 2-methyl-6-nitrobenzoic anhydride in tetrahydrofurane. Organic layers of both modified aliquots are quantitatively evaluated. Then they are boiled out a nitrogen flow, a solid residue is resuspended in a mobile phase that is followed by chromatographic fractionation and mass spectrometry of the prepared samples. The presence of endogenous steroids is detected by comparing a retention time and a ratio of characteristic ion intensity in the samples and the reference solutions.

EFFECT: higher accuracy of detecting steroids and reduced blood plasma amount required for the analysis.

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