Development of method for direct multi-elemental analysis of whisky using total reflection X-ray fluorescence

This work describes a method for direct analysis to quantify S, Cl, K, Ca, Ti, V, Mn, Fe, , Cu, Zn, As, Br, , Rb, Ba and Pb in whiskys by total reflection X-ray fluorescence (TXRF). In the optimization step were evaluated the influence of reading time (100, 250, 500 and 1000 s), internal standard-IS (Ga, Y, Ge) and IS concentration (1 and 10 mg L-1) using Johnnie Walker Red Label whisky spiked with contaminants indicated in Brazilian legislation1 (200 μg L-1 Pb and 100 μg L-1 As). Samples with and without spike were analyzed directly and in the optimized conditions the recoveries and relative standard deviations (RSD%) found for Pb and As were 98% and 3% and 102 % and 2%, respectively. The method was applied to 23 whisky samples of three differents brands. The concentration ranges (mg L-1) for the studied analytes were: S (0.9 – 1.5); Cl (0.02 - 2); K (0.7 - 7); Ca (0.26 - 15); Ti (0.,01 – 2.3); V (<LD – 0.1); Mn (0.003 – 0.16); Fe (0.2 - 5.4); Cu (0.04 - 0.9); Zn (0.01 – 0.2); As (<LD - 0.01); Br (0.003 – 0.01); Rb (<LD – 0.01); Ba (<LD – 9.4) and Pb (<LD - 0.2). Most of the whisky samples had As and Pb concentrations below of the established by Brazilian legislation1. The developed method is simple, fast, consumes few reagents and allows multi-elemental determination.