Determination of total arsenic in soft drinks by hydride generation atomic fluorescence spectrometry

A highly sensitive and simple method has been developed for the determination of total arsenic, by continuous hydride generation and atomic fluorescence spectrometry (HGAFS), in refreshing drink samples as colas, teas and fruit juices. Samples were mixed with concentrated HCl and KI to obtain final concentrations of 2 mol l⁻¹ and 1%, respectively. These solutions were aspirated and merged with a reducing NaBH₄ 3% (m/v) solution, with sample and NaBH₄ flow rates of 12.5 and 1.5 ml min⁻¹, respectively. The hydride generated in a 170 cm reaction coil was transported to the detector with an Ar flow of 400 ml min⁻¹. The recovery values of added concentrations, from 0.1 to 0.9 ng ml⁻¹, of arsenic in colas, teas and fruit juices were 94 ± 5, 101 ± 9 and 94 ± 6, respectively, achieving variation coefficients between 0.1% and 9%, confirming the accuracy of developed procedure. Detection limit, ranged from 0.01 to 0.03 ng ml⁻¹. On comparing the direct determination with a reference procedure made after dry ashing operation it can be noticed that the direct approach provides a simplification of the handling and time consuming, achieving statistically comparative results.