Determination of selected elements by X-ray fluorescence spectrometry in liquid drug samples after the preconcentration with thioacetamide

Preconcentration performance characteristics of precipitation of Mn, Fe, Co, Cu, Zn, Pb, Hg, and Cd and with subsequent filtration through cellulose nitrate membrane were investigated for the X-ray spectrometry identification and determination of trace metal ions in drug samples. The method was optimised for several parameters, including pH and amount of thioacetamide. The investigated analyte ions were collected on cellulose nitrate membrane filter (Pragopor 4) as sulphides after the reaction with thioacetamide. Optimal reaction conditions were found out (pH 8.5 for Fe, Zn, Hg, and Cd and pH 11.5 for Mn, Co, Cu, and Pb; 1.2 mL of added thioacetamide). Thereafter, the content of these elements was determined in the samples of drugs—NaCl, glucose and dextrane. The rapidity of this method, its polycomponent character and low detection limits (for filters: Mn—1.09 μg, Fe—1.08 μg, Co—0.82 μg, Cu—0.42 μg, Zn—0.61 μg, Pb—0.45 μg, Hg—0.42 μg, and Cd—0.99 μg) have proved this method to be very promising in rapid screening used in quality control of drugs.