A solid phase extraction method was developed for the direct determination of nickel in alcoholic beverages. This method is based on the adsorption of nickel onto the peel of Citrus reticulata (mandarin orange). The solution pH, amount of adsorbent, sample and eluent flow rates, eluent concentration and matrix effects were investigated using multivariate optimization strategies. Desorption studies were carried out with 1 mol L-1 HCl. The optimum extraction conditions were obtained using a sample pH of 6.0, sample flow rate of 4.3 mL min-1, 50 mg of sorbent mass and 1.0 mol L-1 HCl at a flow rate of 2.0 mL min-1 used as eluent. The preconcentration factor, precision, limit of detection (LOD), limit of quantification (LOQ), consumption index and sample throughput were estimated as 12, 0.9% (30.0 µg L-1, n = 7), 3.1 µg L-1, 10.3 µg L-1, 0.85 mL and 15 samples per h, respectively. The method was applied to sugar cane spirit and whisky samples and the results for recovery tests were higher than 99%.
nickel; preconcentration; mandarin peel; cane spirit; whisky
