Measurement of testosterone and pregnenolone in nails using gas chromatography-mass spectrometry

An efficient method for the determination of testosterone and pregnenolone in human nails using gas chromatography-mass spectrometry (GC-MS) with d(3) -testosterone as an internal standard is described. The method involves alk aline digestion and liquid-liquid extraction, with subsequent conversion to mixed pentafluoropenyldimethylsilyl-trimethylsilyl (flophemesyl-TMS) deriv atives for sensitive analysis in the selected-ion monitoring (SIM) mode. Th e limit of detection (LOD) and limit of quantification (LOQ) were lowered t o 0.1 and 0.2 pg/g, respectively, when 100 mg of nail-clippings were used. The mean recoveries of testosterone and pregnenolone were 89.8 and 86.7%, r espectively, while good overall precision (% C.V.; 4.5-9.5) and accuracy (% bias; 3.9-8.4) were demonstrated. Linearity as a correlation coefficient w as 0.9913 (testosterone) and 0.9965 (pregnenolone). When applied to fingern ail and toenail samples from seven healthy men and nine healthy women, test osterone and pregnenolone were positively detected in the concentration ran ge of 0.24-5.80 ng/g. The levels of two steroids studied in the nails were found to be higher in the male subjects than in the female subjects, and ex cept for the toenails of the females, the levels of testosterone were highe r than those of pregnenolone. (C) 2001 Elsevier Science B.V. All rights res erved.