Extraction of trace methamphetamine in humanurine.

Abstract

The determination of methamphetamine in human urine was worked by GC/MS. All of the trace methamphetamine in human urine could not be extracted with organic solvent. However, the extraction percent was about 98101% when 0.5 ml of aqueous solution saturated with di-n-hexylamine was added to the urine. The recommended procedure is as follows: place 100 ml of urine containing less than 150 ng of methamphetamine.HCl, 5 ml of 15% sodium carbonate solution, 0.5 ml of aqueous solution saturated with di-n-hexylamine, and 10 ml of chloroform in a 200 ml separatory funnel. Shake it for 1 min and centrifuge for 5 min at 3000 rpm. In a 10 ml test tube, place 5 ml of the chloroform phase, 1 ml of 143 ng/ml diphenylamine chloroform solution, and 0.4 ml of 95% trifluoroacetic anhydride ethyl acetate solution. Warm it on a water bath for 30 min at 50±3°C, and evaportate chloroform on a water bath for 10 min at 75±5°C. Determine the trifluoro-acetyl derivative of methamphetamine by GC/MS. The extraction efficiency was 100.3% when as little as 7.98 ng of methamphetamine·HCl was tested. When the amount of methamphetamine in human urine was less than 75 ng, the extraction efficiency of methamphetamine was higher in the presence of di-n-hexylamine compared to that without the base.