Identification of human urine stains by HPLC analysis of 17-ketosteroid conjugates

A new method for identifying human urine stains utilizing high-performance liquid chromatographic (HPLC) analysis of five major 17-ketosteroid conjugates: dehydroepiandrosterone sulfate, etiocholanolone sulfate, etiocholanolone glucuronide, androsterone sulfate, and androsterone glucuronide was examined. Samples of urine stains were extracted with borate buffer solution (pH 9.3) and the extracts were applied onto a Sep-Pak tC18 cartridge. The analytes were eluted from the cartridge with methanol. The eluates were prelabeled with 2,4-dinitrophenylhydrazine in trichloroacetic acid-benzene solution and were separated by HPLC on a reversed-phase ODS column using a mobile phase of 80% methanol in a buffer consisting of 25 mM sodium acetate in 2% acetic acid. The eluates were monitored by a spectrophotometer at 380 nm. While all five 17-ketosteroid conjugates were clearly detected in the human urine stain samples, traces of only some of these conjugates were detected in the animal samples. Therefore, the presence of all five 17-ketosteroid conjugates indicated human specificity. In addition to the above finding, the properties of those five 17-ketosteroid conjugates were confirmed by electrospray ionization liquid chromatography-mass spectrometry (ESI-LC-MS).