Determination of amphetamine and methylamphetamine by gas-liquid chromatography (head space).

1 A method for determining amphetamine and methylamphetamine in urine by gas-liquid chromatography is described. 2 Chromatography is performed on a 10% Apiezon L, 10% KOH column with alkali-flame detection (NPD). This method avoids the losses of these volatile substances which are known to occur when solvent extraction is used. An alkalinized urine sample (1 ml) is introduced into a sealed vial which is heated in a water bath at 70 degrees C for 20 min. A 1 ml portion of the gas phase in equilibrium with the liquid phase is chromatographed. 3 Amphetamine and methylamphetamine can be detected and measured in urine samples after single therapeutic doses of the drugs.