Abstract
Methamphetamine hydrochloride in a methamphetamine hydrochloride and ephedrine hydrochloride mixture was determined indirectly by atomic absorption spectrophotometry of bismuth, the recommended procedure is as follows : A sample is dissolved in water, to which 1 ml of 7% HCl, and 1 ml of KI-BiCl3 aqueous solution (7% KI solution saturated with BiCl3) are added. The total volume of the solution is brought to 10 ml with water. The solution is allowed to stand for 30 minutes, and filtered. To one ml of the filtrate is added 1 ml of conc. HCl, and it is diluted to 25 ml with water, and then bismuth is determined by atomic absorption spectrophotometer. The respective presence of 0.04 times NaCl, 0.21 times Ca 2+, 0.20 times Mg 2+, 2.04 times Al 3+, 2.05 times K +, 10.97 times glucose, 7.3 times ephedrine hydrochloride did not interfere the determination, whereas Na2S2O3 interfered at the copresence of 0.41 times. The interference of metal ion and Na2S2O3 on the determination of methamphetamine hydrochloride were eliminated by the extraction of methamphetamine from the basic aqueous solution into chloroform. Determination limit for the methamphetamine hydrochloride is 16 μg/ml.
