Determination of 5 Elements in Tobacco Flavor and Liquor by Inductively Coupled Plasma Mass Spectrometry with Graphite Digestion and Dynamic Reaction Cell Mode

The tobacco flavor and liquor sample (0.3 g, accurate to 0.001 g) was placed into the digestion tank of an automatic graphite digestion instrument, and 10 mL of nitric acid and 1 mL of perchloric acid in total were added three times as digestion solution. The sample was completely digested at the maximum digestion temperature of 170℃, then the obtained solution was made its volume up to 50 mL by water, and arsenic, lead, cadmium, chromium and nickel in the solution were determined by inductively coupled plasma mass spectrometry (ICP-MS). The determined isotopes of chromium, cadmium, nickel, lead and arsenic were ⁵²Cr, ¹¹¹Cd, ⁶⁰Ni, ²⁰⁸Pb and ⁷⁵As, respectively, with indium as internal standard element, and dynamic reaction cell (DRC) mode was used to eliminate the mass spectral interference of chromium and arsenic. Helium collision mode was used for determination of chromium, cadmium, nickel and lead, while hydrogen reaction mode was used for determination of arsenic. As shown by the results, linear relationships between the mass concentrations of 5 element and the count values ratio of each element to the internal standard were found in definite ranges, with detection limits (3s) in the range of 0.016-0.035 mg·kg^-1. Test for recovery was made by standard addition method, giving results in the range of 91.5%-111%, with RSDs (n=6) of the determined values ranged from 0.28% to 3.1%. The proposed method was applied to analysis of 10 tobacco flavor and liquor samples. The detected amounts of chromium, arsenic and nickel were 0.019-0.061 mg·kg^-1, 0.039-0.061 mg·kg^-1 and 0.022-0.031 mg·kg^-1, respectively, while cadmium and lead were not detected.