Inorganic antimony speciation using tungsten coil atom trap and hydride generation atomic absorption spectrometry

Akay, Pınar
Antimony is a toxic element which is mostly found in two oxidation states (III and V) in environmental, biological and geological samples. Antimony may form various inorganic and organic compounds that exhibit differences in analytical behavior, toxicity and mobility; inorganic compounds of antimony are more toxic than organic forms and toxicity of Sb(III) has been shown to be 10 times higher than that of Sb(V). Therefore selective determination of Sb(III) and Sb(V) is required in environmental and biological samples. Hydride generation atomic absorption spectrometry is a sensitive, fast and economical technique for the determination of antimony at trace level. A possible non-chromatographic method for antimony speciation is hydride generation atomic absorption spectrometry that is based on the relatively slow kinetics of hydride formation from Sb(V). In this study, continuous flow hydride generation method for the determination of antimony was developed and hydride generation conditions were optimized. Analyte solution was prepared in 0.050 mol/L HCl and 1.2% (w/v) NaBH4 stabilized in 0.30% (w/v) NaOH was used as a reductant solution. Inorganic antimony speciation conditions were determined by continuous flow HGAAS system. For the pre-reduction of Sb(V) to Sb(III), 8.0% (w/v) potassium iodide (KI) and 0.10% (w/v) ascorbic acid were used. Further speciation study was also carried out using Ir coated W-coil Atom Trap Hydride Generation Atomic Absorption Spectrometry. Tungsten coil atom trap was used to enhance the sensitivity. Tungsten coil surface was treated with Ir and totally 250 μg 1000 mg/L Ir stock solution was used for coating of tungsten coil. LOD and LOQ values were calculated as 152 pg/mL and 508 pg/mL according to 120 seconds trapping. 128 and 37 fold enhancement were obtained for 120 seconds collection with respect to W-coil-ETAAS and ETAAS, respectively.
Citation Formats
P. Akay, “Inorganic antimony speciation using tungsten coil atom trap and hydride generation atomic absorption spectrometry,” M.S. - Master of Science, Middle East Technical University, 2010.