Is deproteinization necessary in the determination of human plasmatic steroids by GC/IT-MS/MS analysis?

Abstract

Human plasma is composed on average of 7% of proteins, where the main one is albumin, with concentrations range of 3.2-4.8 g/dL. Many studies consider plasmatic proteins to be a problem in relation to plasma analysis, so they must be eliminated. In this work, we have performed sev- eral deproteinization tests with acetonitrile, methanol, ethanol, HCl 0.5 M/methanol (1:1) (v/v), trichloroacetic acid (10%), sulfosalicylic acid (20%) and perchloric acid, proteases and activated carbon before analyzing twelfe plasmatic steroids hormones using gas chromatography directly coupled ion-trap mass spectrometry. Signal/noise ratios of tests were determine to assess wheth- er a previous deproteinization treatment is necessary or not prior to their analysis. The use of chemical deproteinization methods, proteases and active carbon did not improve the signal/noise ratio. Deproteinization is not required for the analysis of steroid hormones in plasma using gas chromatography-directly coupled ion-trap mass spectrometry. Keywords: