Determination of copper in wine by ETAAS using conventional and fast thermal programs: Validation of analytical method

摘要

A study involving conventional and fast thermal programs, with and without matrix modifiers, for the determination of Cu in wine by ETAAS is presented. With the conventional thermal program, better results were obtained when using matrix modifiers [PdNO3 and Mg(NO3)(2)]. This program presents better sensitivity and consequently it was the program selected for method validation.The fast thermal program allows a higher throughput and can be a useful alternative to the conventional program. The method involves reduced risk of sample contamination eliminating prior treatment other than dilution (1:5).White and red wines with several Cu concentrations were used for method validation. The determination was performed in the linear range of 1-50 mu g L-1; the detection limit in undiluted samples was 5 mu g L-1; the recoveries were between 93% and 100%; the repeatability (n=10), expressed as %RSD, was lower than 3%. Comparable values of concentrations were obtained by ETAAS and ICP-MS (differences < 15%). The advantages of the method (practicability, sensitivity, precision, and accuracy) make it useful for routine determination of this metal in wine, when compared to flame AAS, which inevitably requires either sample pre-concentration or the use of the standard additions method.