Fig. 1. Comon of codeine mass spectra: A, TMS derivative; B,

tiifluoroacetyl derivative allylic alcohol moiety of codeine. The TMS derivatives can be injected directly into the GC/MS, and do not require a drying step-an advantage compared with the acetyl deri-vatization procedure. We found acid hydrolysis better than enzymatic hydroly-sin for liberation ofthe conjugated opiates. Analytical recov-eries Qarger peaks) of morphine were better and the acid hydrolysis is shorter than the enzymatic procedure, which takes several hours or an overnight incubation. Opiates decompose, however, if urine is refluxed for>30 mm. Similar findings were noted by Fish and Hayes (5). Operating in the “scan ” mode, the on-column sensitivity for morphine is about 40 ng (with a signal/noise ratio>10), indicating the method has sufficient sensitivity for use in drug testing and confirmation. References 1. Mathia DF, Budd RD. GLCPI’LC analysis of codeine and mor-phine in urine via derivatization techniques. Clin Toxicol 1980;16:181-8. 2. Lhoeat G, Mercier M. Gas chromatography-selected ion monitor-ing applied to the determination of codeine in plasma. Pharm Act