Application of rapid electrothermal atomic absorption spectrometric methods to the determination of Ag, Al, Cd and Mn in cocaine and heroin samples

 Rapid methods were developed for the direct determination of Ag, Al, Cd and Mn in cocaine and heroin by ETAAS using programmes omitting the charring step . Sample pretreatment was simple: dissolution in ultrapure water or in 35.0% (v/v) HNO₃ for heroin or cocaine, respectively. Optimum drying temperatures were 250 °C for Ag, Al and Mn, and 300 °C for Cd. The run cycles were 35 and 37 s, for Ag and Al respectively, and 36 s for Cd and Mn. The best results were obtained with Pd, Mg(NO₃)₂ and (NH₄)₂HPO₄, as chemical modifiers. The limits of detection were 8.6, 55.9, 2.2 and 12.4 μg kg^-1 for Ag, Al, Cd and Mn, respectively. Received: 14 November 1996/Revised: 14 January 1997/Accepted: 18 January 1997