SLURRY SAMPLING FOR HYDRIDE GENERATION ATOMIC-ABSORPTION SPECTROMETRIC DETERMINATION OF ARSENIC IN CIGARETTE TOBACCOS

The development of a slurry sampling hydride generation atomic absorpt ion spectrometric (HGAAS) method for the determination of arsenic in c igarette tobacco samples is described, The method is relatively simple and has been shown to give values of total arsenic close to those obt ained using methods requiring total dissolution and decomposition of a ll vegetable matter before analysis, Pre-treatment of samples slurried in nitric acid by ultrasonication permitted the extraction of about 9 0% of the total arsenic from tobacco samples. Further improvement in t he recovery efficiency (up to 93-94%) was accomplished by the use of a n additional step of short microwave-accelerated treatment. L-Cysteine was used as a pre-reduction agent, The accuracy and precision of the slurry sampling HGAAS method were studied using the certified referenc e material (CRM) CTA-OTL-1 Oriental Tobacco Leaves, Under the optimum conditions, as little as 2.6 ng of arsenic can be detected. The relati ve standard deviation of the overall procedure was calculated to be be low 7.6% at arsenic concentration levels of 0.5-0.9 mg kg(-1) and the analytical results obtained for the CRM agreed with the certified valu e, The main factors that influenced the reliability of the method were sample homogeneity, particle size and slurry concentration.