FLOW-INJECTION ANALYSIS WITH AMPEROMETRIC DETECTION OF COCAINE IN CONFISCATED SAMPLES

Flow injection analysis (FIA) with amperometric detection is applied t o the determination of cocaine. Flow parameters were optimised prior t o electrode calibration: a detection potential of +1 V vs. Ag/AgCl/sat . KCI and a flow rate of 2.5 ml min(-1) resulted adequate. A relative standard deviation of 1.7% was calculated for a concentration level of 6.2x10(-6) (n=12) without carrying out a carbon paste electrode pretr eatment. Calibration curves were found to be linear between 2x10(-7) a nd 10(-5) M, and the method has a detection Limit of 2x10(-7) M. A sim ple and reproducible procedure is proposed for the determination of co caine in illegal dosage forms confiscated by police authorities. The m ethod compared favourably with liquid chromatography with UV detection .