Determination of methamphetamine and its metabolites in rat tissues by gas chromatography with a nitrogen-phosphorus detector.

A method for the determination of methamphetamine and its metabolites in tissues of the rat receiving methamphetamine was developed using gas chromatography with nitrogen-phosphorus detection. The extraction procedure, volatility of various derivatives, the acylation procedure, mass spectra of various derivatives and the recovery of methamphetamine and its metabolites in rat tissues are reported. The detection limits of pentafluorobenzoyl derivatives of methamphetamine and amphetamine, and heptafluorobutyryl derivatives of p-hydroxymethamphetamine and p-hydroxyamphetamine, were ca. 0.1 and 0.15 ng, respectively. This method could be used to determine concentrations as low as 10-15 ng/g of methamphetamine and its metabolites; recoveries from the rat brain, liver and serum were 94-106, 103-115 and 94-96%, respectively.