尿中覚せい剤の抽出・誘導体化及びGC/MSの全自動分析

The method for the automatic analysis of methamphetamine (MA) and amphetamine (AP) in the urine was developed using a prepstation in combination with a GC/MS instrument. A prepstation can automate many pretreatment steps, such as solid phase extraction (SPE) and derivatization. Human interaction is only required to load the urine samples into vials, cap them and place them on the auto sampler tray. All of the following steps were automated : 1) An urine sample of 1.5 ml was injected into the SPE cartridge (DAU), where MA and AP were retained. 2) The cartridge 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-methanol (0.5 ml) from the washed cartridge. 4) The elute was evaporated and dried. Then a 4N sodium hydroxide (0.02 ml) and a 10 ppm diphenylmethane in dichlormethane (0.2 ml) internal standard (I.S.) solution were added and stirred. 5) A derivatizing reagent, N-methyl-bis-trifluoroacetamide (MBTFA) was added into the sample. 6) And finally, the reaction mixture was injected into the GC/MS instrument for analysis. The total analysis time for 10 samples was approximately 10 h and 20 min. The calibration curves, using the I.S. method, demonstrated good linearity throughout the concentration range from 0.1 to 10 μg/ml for both MA and AP. Using a scan mode the detection limits were 20 ng/ml for both 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 using the scan mode for a 1 μg/ml sample was 5.9% for MA and 6.0% for AP.