Testing of the anabolic stanozolol in human hair by gas chromatography-negative ion chemical ionization mass spectrometry

A sensitive, specific and reproducible method for the quantitative determin ation of stanozolol in human hair has been developed. The sample preparatio n involved a decontamination step of the hair with methylene chloride and t he sonication in methanol of 100 mg of powdered hair for 2 h. After elimina tion of the solvent, the hair sample was solubilized in 1 ml 1 M NaOH, 15 m in at 95 degrees C, in the presence of 10 ng stanozolol-d(3) used as intern al standard. The homogenate was neutralized and extracted using consecutive ly a solid-phase (Isolute C-18) and a liquid-liquid (pentane) extraction. A fter evaporation of the final organic phase, the dry extract was derivatize d using 40 mu l MBHFA-TMSI (1000:20, v/v), incubated for 5 min at 80 degree s C, followed by 10 mu l of MBHFBA, incubated for 30 min at 80 degrees C. T he derivatized extract was analyzed by a Hewlett-Packard GC-MS system with a 5989 B Engine operating in the negative chemical ionization mode of detec tion. Linearity of the detector response was observed for stanozolol concen trations ranging from 5 to 200 pg/mg with a correlation coefficient of 0.99 8. The assay was capable of detecting 2 pg of stanozolol per mg of hair whe n approximately 100 mg hair material was processed, with a quantification l imit set at 5 pg/mg. Intra-day precision was 5.9% at 50 pg/mg and 7.8% at 2 5 pg/mg with extraction recoveries of 79.8 and 75.1%, respectively. The ana lysis of a 3-cm long hair strand, obtained from a young bodybuilder (27 yea r old) assuming to be a regular user of Winstrol (stanozolol, 2 mg), reveal ed the presence of stanozolol at the concentration of 15 pg/mg. (C) 2000 El sevier Science B.V. All rights reserved.