Determination of steroidal hormones in urine samples by micellar liquid chromatography following solid-phase extraction

Steroidal hormones were determined in spiked urine samples using micellar m obile phases of sodium dodecyl sulphate (SDS)-pentanol, solid-phase extract ion (SPE), and detection in the UV region. In the optimized procedure, a 10 mL aliquot of urine sample is loaded into a C-18 cartridge and washed with 2 mL of 50:50 (v/v) methanol-water, followed by 200 muL of 70:30 (v/v) met hanol-water. The retained steroids are eluted with 2 mt of methanol and the eluate evaporated to dryness under nitrogen at 50 degreesC. The residue is redissolved with 200 muL of the micellar mobile phase used i n the chromatographic separation and injected into the chromatograph. The p erformance of the procedure was checked for 13 steroidal hormones: dehydrot estosterone, methandienone, methenolone enanthate, methyltestosterone, dydr ogesterone, medroxyprogesterone, medroxyprogesterone acetate, nandrolone, n androlone decanoate, progesterone, testosterone, testosterone enanthate, an d testosterone propionate. Limits of detection were below 5 ng/mL for all steroids except nandrolone, nandrolone decanoate, and testosterone enanthate, whose elution from the SP E C-18 column was not quantitative.