Automated qualitative and quantitative metabolic profiling analysis of urinary steroids by a gas chromatography-mass...

A computer system (MSSMET), using methylene unit retention indices for an off-line reverse library search analysis of selected ion chromatograms from gas chromatography-mass spectrometry data, has been applied to the qualitative and quantitative determination of urinary steroids. Several published methods for the isolation and derivatization of urinary steroids were evaluated for reproducibility using fused silica capillary column gas chromatography. Using a procedure that gave the greatest reproducibility, MSSMET analyses of urinary steroids were evaluated with packed (3-m 3% OV-101) and capillary (50-m OV-101 WCOT fused silica) columns. Most urinary steroids could be accurately quantitated using the packed column. However, urinary steroids with similar mass spectra and retention behavior on a packed column (i.e., androsterone and etiocholanolone, or 3 alpha, 11 beta, 17 alpha, 21-tetrahydroxy-5 beta-pregnane-20-one and 3 alpha, 11 beta, 17 alpha, 21-tetrahydroxy-5 alpha-pregnane-20-one) were completely separated using the capillary column and could be reproducibly quantitated with a 2-sec scan cycle time (10-15 data points across a peak) but not with a longer scan cycle time. Overloading was the major problem encountered with the fused silica capillary column.