SIMULTANEOUS DETERMINATION OF METHAMPHETAMINE AND ITS METABOLITES IN THE URINE SAMPLES OF ABUSERS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHYWITH CHEMILUMINESCENCE DETECTION

A HPLC determination method for methamphetamine (MA) and its metabolit es in the urine samples of abusers has been developed. MA, amphetamine (AP), norephedrine (NE), p-hydroxymethamphetamine (pOHMA), p-hydroxya mphetamine (pOHAP) and an internal standard, namely beta-phenylethylam ine (PEA) were derivatized with dansyl chloride. They were separated o n a reversed phase column with gradient elution using an acetonitrile/ tetrahydrofuran/imidazole buffer mobile phase and chemilumigenically d etermined using bis(2,4,6-trichlorophenyl)-oxalate/hydrogen peroxide a s post column reagents. The lower determination limits were as low as 1 x 10(-14)-3 x 10(-14) mol. AP, NE, pOHAP and PEA were derivatized wi th naphthalene-2,3-dicarboxaldehyde, and were separated on a reversed phase column using an acetonitrile/imidazole buffer mobile phase and c hemilumigenically determined. The lower determination limits were 3 x 10(-16)-1.5 x 10(-15) mol. Enzymatic hydrolysis of glucuronides of pOH MA (pOHMAG) and pOHAP (pOHAPG) allowed them to be determined as pOHMA and pOHAP, respectively. After adjusting the pH of the urine samples t o 10.5 and adding PEA, all metabolites except glucuronides were extrac ted quantitatively into chloroform-isopropanol (3:1). Utilizing the tw o methods, MA and all metabolites were determined in urine samples of MA abusers. The tendency, in order of decreasing concentration was: [M A] > [A] > [pOHMAG] > [pOHMA] > [NE] > [pOHAPG] > [pOHAP]. Although ep hedrine (EP) was detected in several samples, it was not considered to be a metabolite of MA but rather a component derived from cough medic ine.