Hydride generation-in situ trapping-flame atomic absorption spectrometry hybridization for indium and thallium determination

Abstract

The analytical performance of coupled hydride generation-integrated atom trap (HG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system was evaluated for determination of In and Tl in reference material. Indium, using formation of InH3 and TlH vapors were atomized in air-acetylene flame-heated IAT. A new design of HG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangements (a water-cooled single silica tube, double-slotted quartz tube or an "integrated trap") was investigated. A dramatic improvement in detection limits was achieved compared with that obtained using either of the atom trapping techniques, presented above, separately. The detection limits, defined as 3 times the blank standard deviation (3σ), were 0.60 and 0.40 ng mL-1 for In and Tl, respectively. For a 120 s in situ preconcentration time (sample volume of 2 mL), sensitivity enhancement compared to flame AAS, were 417 and 450 folds for In and Tl, respectively, using hydride generation-atom trapping technique. The sensitivity can be further improved by increasing the collection time. The precision, expressed by RSD, was 4.4% and 5.2% (n = 6) for In and Tl, respectively. The designs studied included slotted tube, single silica tube and integrated atom trap-cooled atom traps. The accuracy of the method was verified by the use of certified reference material (GBW 07302 Stream Sediment) and by aqueous standard calibration solutions. The measured In and Tl contents, in reference material, were in satisfactory agreement with the certified or information values. ©2007 Sociedade Brasileira de Química.