Development and validation of a quantitative gas chromatography-mass spectrometry method for the detection of...

A quantitative method based on gas chromatography-mass spectrometry (GC-MS) has been developed for the detection of 16 endogenous androgens in the urine of mice. The substances are extracted from 100 microL urine with freshly distilled diethyl ether after alkalinisation. The substances are derivatised with a mixture of N-methyl-N-trimethylsilyltrifluoroacetamide/NH(4)I/ethanethiol (383/1/2, v/w/v) and detected by GC-MS in the selected ion monitoring mode. The results of the method validation indicate good linearity, accuracy and precision, making the method suitable for the quantification of endogenous androgens in mouse urine. The selectivity of the method showed that no interfering peaks were observed at the retention times of the analytes. The method allows for the direct quantification and identification of testosterone and 15 other endogenous androgens at low concentrations (ng/mL) in mouse urine. The applicability of the method is shown by the analysis of a mouse urine. Several endogenous steroids could be detected.