Comparative analysis of dry ashing and wet digestion methods for determination of Pb metal in tobacco leaves Available to Purchase

Research about validation of Pb analysis methods in tobacco leaves with wet and dry digestions using atomic absorption spectrophotometers has been done. Tobacco samples used were obtained from three regions in Indonesia (Region 1, Region 2, and Region 3). Dry ashing was carried out by heating the sample at 500 °C and dissolving the sample in HNO₃ while wet digestion was done by heating the sample at 100 °C with HNO₃, HClO₄ and H₂SO₄ as oxidizer solutions. Afterwards, the digested solution was analyzed by flame atomic absorption spectrometer. Validation parameters used in this research were linearity, LOD, LOQ, accuracy and precision. The obtained R² from the linearity test was 0.9985, LOD value of the analysis was 0.2 ppm, and the LOQ was 0.6 ppm. The average accuracy of dry ashing for the standard solution with concentration of 1, 2 and 3 ppm was 71.674%. Meanwhile, the average recovery for the wet digestion with the 3 concentrations was 83.562% which indicated that only the accuracy data of wet digestion was included in the AOAC acceptance recovery range of 80-110%. Precision value for the dry ashing was 10.707% and for the wet one was 10.288%. Both precision data were included in the acceptance criteria of 11%. The Pb concentration detected from both digestions tobacco leave sample originating from Region 1, Region 2 and Region 3 were higher than 12 µg/g, in which the wet digestion method was found to be more reliable.