A simple yet effective GC/MS protocol was developed and evaluated for the determination of free codeine, free morphine, 6-acetylmorphine, total codeine and total morphine in urine. Optimal recovery was achieved with extraction conducted at pH 9.0. Trimethylsilyl-derivatives of these analytes and the internal standard (nalorphine) were found adequately stable for a 72-hour period. Quantitative determination of the analytes was performed by selective ion monitoring. Excellent linearity was observed over the 50-1000 ng/mL concentration range studied. The intraday and interday precisions range from 0.47 to 7.72% for codeine, 0.31 to 8.09% for morphine and 0.49 to 6.15% for 6-acetylmorphine. The overall recoveries for codeine, morphine and 6-acetylmorphine were found to be 98.3%, 76.7% and 85.6% respectively.
Lin, D.-L.; Shaw, K.-P.; and Chen, C.-Y.
"Determination of codeine, morphine and 6-acetylmorphine in urine,"
Journal of Food and Drug Analysis: Vol. 4
, Article 9.
Available at: https://doi.org/10.38212/2224-6614.3004