Abstract
A HPLC determination method for methamphetamine (MA) and its metabolites in the urine samples of abusers has been developed. MA, amphetamine (AP), norephedrine (NE), p-hydroxymethamphetamine (pOHMA), p-hydoroxyamphetamine (pOHAP) and an internal standard, namely β-phenylethylamine (PEA) were derivatized with dansyl chloride. They were separated on a reversed phase column with gradient elution using an acetonitrile/tetrahydrofuran/imidazole buffer mobile phase and chemilumigenically determined using bis(2, 4, 6-trichlorophenyl)-oxalate/hydrogen peroxide as post column reagents. The lower determination limits were as low as 1×10-14-3×10-14mol. AP, NE, pOHAP and PEA were derivatized with naphthalene-2, 3-dicarboxaldehyde, and were separated on a reversed phase column using an acetonitrile/imidazole buffer mobile phase and chemilumigenically determined. The lower determination limits were 3×10-16-1.5×10-15mol. Enzymatic hydrolysis of glucuronides of pOHMA (pOHMAG) and pOHAP (pOHAPG) allowed them to be determined as pOHMA and pOHAP, respectively. After adjusting the pH of the urine samples to 10.5 and adding PEA, all metabolites except glucuronides were extracted quantitatively into chloroform-isopropanol (3 : 1). Utilizing the two methods, MA and all metabolites were determined in urine samples of MA abusers. The tendency, in order of decreasing concentration was : [MA]>[A]>[pOHMAG]>[pOHMA]>[NE]>[pOHAPG]>[pOHAP]. Although ephedrine (EP) was detected in several samples, it was not considered to be a metabolite of MA but rather a component derived from cough medicine.
