Determination of stimulants in a single human hair sample by high-performance liquid chromatographic method with...

Stimulants that are controlled by the Stimulant Drug Control Law of Japan are methamphetamine (MA) and amphetamine (AP). MA is used by most stimulant addicts, and AP is detected as its main metabolite. We have developed a high-performance liquid chromatography method with chemiluminescence detection (CL-HPLC), for determining trace levels of MA and its metabolites in a single human hair sample, in which bis(2,4,6-trichlorophenyl)oxalate and hydrogen peroxide are the postcolumn reagents. After washing a single hair sample with water and methanol, it was cut into pieces, extracted with a mixed solution of methanol and hydrochloric acid for 1 h under ultra-sonication and allowed to stand at room temperature overnight. Then the organic phase was evaporated to dryness. To the residues, 0.1 mL of carbonate buffer and 0.1 mL of dansyl chloride solution were added and the solution was heated at 45 degrees C for 1 h. An aliquot of the reaction mixture was then subjected to HPLC. MA and AP were chemiluminogenically detected as their dansyl derivatives from a sample of only a single hair. The detection limit was about 2 pg in an injected volume (20 microliters), and about 20 pg in a single hair sample. This detection limit was smaller than that by the gas chromatography/mass spectrometry (selective ion monitoring) method. Our method was useful as a screening test for stimulant users.