This work reports the first application of Diffusive Gradients in Thin-films technique (DGT) for speciation of tellurium oxyanions in natural waters, employing natural cationic exchange phase the montmorillonite mineral clay (MMT) immobilized in agarose hydrogel, with binding phase on DGT device. The physical-chemical parameters and foreign metals did not interfere on sampling. The MMT binding phase presented sorption efficiency between 10 to 40±3%, mechanism of sorption comprises formation of inner-sphere complexes in MMT structure, from weak electrostatic and Pearson acid/base type interactions. Tellurium speciation was by Chemical Vapor Generation technique on-line atomic emission spectrometry (CVG-ICP OES). TeO32- (Te(IV)) was determined by H2Te volatile species and TeO42- (Te(VI)) by microwave assisted prereduction in 6.0 mol L-1 HCl solution and subsequent determination by CVG-ICP OES. From the optimization instrumental parameters for CVG-ICP OES, LOD and LOQ values were determined as 0.098 µg L-1 and 0.3 µg L-1. Laboratory tests performed using synthetic seawater showed recoveries above 95% for DGT device, making it possible to determinate apparent diffusion coefficient for tellurium oxyanions. Applications of the DGT devices in situ was possible to determination tellurium oxyanions in Paraná State coastline (Brazil).

Speciation Analysis of Tellurium in Natural waters by DGT-CVG-ICP OES.

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