Simultaneous determination of acetylcodeine, monoacetylmorphine, and other opiates in urine by GC-MS

In addition to 6-monoacetylmorphine (6-MAM), acetylcodeine (AC) has been suggested as a marker for the use of illicit heroin. We report a sensitive opiate gas chromatographic-mass spectrometric assay that detects AC, diacetylmorphine, and the propionylated derivatives of codeine, morphine, 6- MAM, and norcodeine. The analytes were extracted by solid phase with recoveries from 62 to 98%. The limits of detection (LOD) and quantitation (LOQ) for AC was 0.5 and 1.0 μg/L. The LOD of the other analytes was 2.0 μg/L and the LOQs ranged from 2 to 10 μg/L. The assay was linear for each analyte from the LOQ to 200 μg/L or 400 μg/L (morphine and codeine) with r ≤ 0.996, except for diacetylmorphine which was linear to 100 μg/L with r = 0.994. The within-run and between-run precision were below 10% CV for all analytes. There was no significant hydrolysis of AC to codeine in urine (pH 4.7 and 8.0) after 23 weeks of refrigeration or freezing. After storage at room temperature in urine of pH 8.0, AC was completely hydrolyzed after 5 weeks, but at pH 4.7, 58% of the AC remained after 15 weeks of storage at room temperature. The sensitivity of this assay was adequate to detect AC in the urine of heroin abusers. In preliminary studies, AC was detected in 6 of 69 opiate positive urines. Concentrations ranging from 1 to 48 μg/L were observed. These concentrations were found to be low when compared with the concentrations of 6-MAM, codeine, and morphine also detected in the urines.