Determination of lead in wine and rum samples by flow injection-hydride generation-atomic absorption spectrometry

Abstract

A method for direct determination of lead in wine and rum samples was developed, using a flow injection hydride generation system coupled to an atomic absorption spectrometer with flame-quartz atomizer (FI-HG-AAS). Lead hyride (PbH 4) was generated using potassium ferricyanide (K 3Fe(CN) 6), as oxidant and sodium tetrahydroborate (NaBH 4) as reductant. Samples were acidified to 0.40% (v/v) HCl for wine and to 0.30% (v/v) HCl for rum, which were then mixed on-line with 3% (m/v) K 3Fe(CN) 6 solution in 0.03% (v/v) HCl prior to reaction with 0.2% (m/v) alkaline NaBH 4 solution. Lead contents of a rum and two different red wine samples were determined by FI-HG-AAS agreed with those obtained by ICP-MS. The analytical figures of merit of method developed were determined. The calibration curve was linear up to 8.0 μg L −1 Pb with a regression coefficient of 0.998. The relative error was lower than 4.58%. The relative standard deviation ( n = 7) was better than 12%. A detection limit of 0.16 μg L −1 was achieved for a sample volume of 170 μL.