Resumo:
Due to the high degree of thallium toxicity and possible contamination of the environment due to the natural presence or by anthropic action in this paper, a simple and fast method for the separation and pre-concentration of thallium in water samples using paper is proposed. chromatographic filter as a solid support with subsequent determination by using high-resolution continuum source graphite furnace atomic absorption spectrometry and direct solid sample analysis(SS HR-CS GF AAS). The chromatographic filter paper disk and EDTA solution were used as the solid phase and masking agent respectively. An investigation of the variables that influence the pre-concentration, such as the pH of the sample, stirring time, sample volume, effect of other species, type and concentration of the masking reagent, was carried out. After optimizing these variables, the analytical method developed showed a preconcentration factor of 57, an precision of 9.4% (thallium solution 10 μg L -1), a limit of detection of 0.0169 µg L-1 and a limit of quantification of 0.0563 µg L-1. Addition and recovery tests were performed and the results varied from 91% to 110%.The accuracy of the method was assessed by analyzing the certified reference material of TDMA 52.4 fortified water and by analyzing water samples using a comparative method that employed an inductively coupled plasma mass spectrometer (ICP-MS). The procedure was applied for the determination of thallium in water samples collected in the city of Barreiras, Bahia, Brazil. The thallium concentrations present in the analyzed samples ranged between 0.0814 and 0.802 μg L-1. The method proved to be simple, fast, efficient and easy to perform for the determination of thallium by SS HR-CS GF AAS.
