Graphite-assisted laser ablation dielectric barrier discharge optical emission spectrometry for rapid detection of cadmium and zinc in cigarettes

A study of the capability of graphite-assisted laser ablation dielectric barrier discharge optical emission spectrometry (GALA-DBD-OES) for direct analysis of cadmium and zinc in cigarettes was undertaken. GALA-DBD-OES allowed direct sampling of cigarette samples in the condensed phase with the irradiation of a continuous wave infrared laser for subsequent atomization/excitation by a DBD plasma. The graphite in the sample matrix functioned as a laser energy converter and a thermal transmitter to improve the desorption efficiency of analytes. Under optimal conditions of the plasma gas flow rate, the discharge current and the proportion of graphite in the matrix, Cd and Zn were detected with limits of detection of 0.09 μg/g and 0.20 μg/g, respectively. Inter-day relative standard deviations of 4.5% for Cd at 45 μg/g and 2.6% for Zn at 30 μg/g indicate a good method repeatability. The accuracy of the present technique was verified by analyzing a certified reference material of cigarette. Quantitative results of Cd and Zn in commercial cigarettes allowed direct comparisons of cigarettes of different prices and geographical locations. All these features suggest the promising role of GALA-DBD-OES as a routine tool for real-time and on-site analysis of heavy metals in cigarettes.