Preparation of high sensitive screening chip of methamphetamine in urine by use of Simon's reagent.

Abstract

A high sensitive and selective screening chip for the detection of methamphetamine in the human urine was developed by use of Simon's reagent and silica gel TLC plate. Equal volume of 2% sodium nitroprusside and 5% sodium carbonate solution was thoroughly but carefully sprayed on the plate, and then it was dried at 110°C for 3 h, followed cutting to ca. 3×1.5 cm chip after cooling. The chip could be detected over 10 ng of methamphetamine by color reaction in acetaldehyde gas. Detection ability of the chip stocked in dessicator did not fall at least after 3 months. The analytical method of the sample urine by using this chip was as follows : 5 ml of sample urine was extracted with 2 ml of benzene under basic conditions, and ca. 20 μl of the extract was spotted on the chip, then it was exposed to acetaldehyde gas. Blue color was developed in case of the urine containing methamphetamine over 0.1 μg/ml. The methamphetamine in the extracted solution regarded as positive by this method could be identified by GC-MS after TFA-derivatization. The screening error of this method was about 3%.