Determination of clenbuterol and salbutamol in urine by capillary gas chromatography with capillary columns of 100 microns.

A method to determine clenbuterol and salbutamol in calf urine is described. Two independent extraction procedures using Extrelut (clenbuterol) and octadecylsilica (salbutamol) were used; the extracts obtained were mixed and purified over a cyanopropyl minicolumn. Trimethylsilyl derivatives were prepared and analysed by GC-MS in selected-ion monitoring mode using a fused-silica open tubular capillary column, 10 m x 100 microns coated with 5% phenylmethylsilicone. Splitless injection was optimized to achieve low percentage residual standard deviation of absolute areas. The best conditions were: injection volume 0.5 microliter, column head pressure 22 p.s.i. (1 p.s.i. = 6894.76 Pa), inlet temperature 250 degrees C and glass liner volume 250 microliters. The recoveries of the complete procedure were in the range 50-60% for both compounds.