State Laboratory, Dublin 15, Ireland.
* Chemistry Dept., Trinity College, Dublin 2, Ireland.

The work reported here has successfully automated the existing manual opiate SPE method using a Gilson Automated Sample Preparation with Extraction Cartridges (ASPEC XL) system. The method extracts morphine, codeine, dihydrocodeine and the main metabolite of heroin, 6-monoacetylmorphine (6-MAM), from blood and urine using mixed-mode IST Confirm HCX cartridges. Following off-line derivatisation, the samples are separated by capillary GC and detected by an ion-trap MS in electron ionisation mode. Quantitation is based on peak area ratios of analyte to deuterated internal standards, from calibration curves in the range 0.25-5.0 µg/ml morphine, codeine and dihydrocodeine and 0.05-1.0 µg/ml 6-MAM for urine analysis and 0.05-1.0 µg/ml morphine, codeine and dihydrocodeine and 0.01-0.2 µg/ml 6-MAM for blood analysis.

The method has been optimised and evaluated, with limits of detection of 0.05 µg/ml for the four drugs in both blood and urine, based on a signal-to-noise ratio of 3:1. Recoveries of morphine, codeine, dihydrocodeine and 6 -MAM from blood were 59%, 58%, 57% and 56%, respectively. Recoveries from urine were 87%, 87%, 91% and 58%, respectively. Good correlation was obtained between real samples determined by the manual and automated methods.