THE AUTOMATED EXTRACTION, DERIVATIZATION AND GC MS OF METHAMPHETAMINEAND AMPHETAMINE IN HUMAN URINE/

The method for the automatic analysis of methamphetamine (MA) and amph etamine (AP) in the urine was developed using a prepstation in combina tion with a GC/MS instrument. A prepstation can automate many pretreat ment steps, such as solid phase extraction (SPE) and derivatization. H uman interaction is only required to load the urine samples into vials , cap them and place them on the auto sampler tray. All of the followi ng steps were automated: 1) An urine sample of 1.5 ml was injected int o the SPE cartridge (DAU), where MA and AP were retained 2) The cartri dge was then washed with 1M acetic acid (1 ml) and then with methanol (3 ml). 3) The MA and AP were then eluted using 0.1% sulfric acid-meth anol (0.5 ml) from the washed cartridge. 4) The elute was evaporated a nd dried. Then a 4N sodium hydroxide (0.02 ml) and a 10 ppm diphenylme thane in dichlormethane (0.2 ml) internal standard (I.S.) solution wer e added and stirred. 5) A derivatizing reagent, N-methyl-bis-trifluoro acetamide (MBTFA) was added into the sample. 6) And finally, the react ion mixture was injected into the GC/MS instrument for analysis. The t otal analysis time for 10 samples was approximately 10 h and 20 min. T he calibration curves, using the LS. method, demonstrated good lineari ty throughout the concentration range from 0.1 to 10 mu g/ml for both MA and AP. Using a scan mode the detection limits were 20 ng/ml for bo th MA and AP and using selected ion monitoring (SIM) the limits were 1 ng/ml for MA and 3 ng/ml for AP. The relative standard deviation usin g the scan mode for a 1 mu g/ml sample was 5.9% for MA and 6.0% for AP .