Determination of ultratrace tellurium in water by hydride generation atomic absorption spectrometry using online separation and pre-concentration with nano-TiO2 microcolumn

Abstract

Silica gel loaded with nano-TiO2 was used as solid phase extraction materials to prepare a microcolumn for the online enrichment of trace tellurium in water and then determined by hydride generation atomic absorption spectrometry (HG-AAS). The effect of pH and the flow rate of sample on the extraction efficiency, NaOH concentration on the elution efficiency and other factors influencing hydride generation efficiency of tellurium were carefully investigated. Under the optimized experimental conditions, the sensitivity and the limit of detection (LOD) of this method were 0.009 L/μg and 0.04 μg L−1, respectively, which were 1000 and 850 times better than those obtained by the traditional flame atomic absorption spectrometry (FAAS); and the LOD for tellurium was improved by 45 times in this work, when compared with that by hydride generation-atomic absorption spectrometry (HG-AAS) without any separation and pre-concentration. This method was found to be interference-free of transitional metal ions, probably because of the surface of the nano-TiO2 was positively charged under acidic conditions, and it does not adsorb their cations. This method was successfully applied to the determination of tellurium in water samples.