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On-line hyphenation of hydride generation with in situ trapping flame atomic absorption spectrometry for arsenic and selenium determination.

The analytical performances of coupled hydride generation, integrated atom trap (HG-IAT) atomizer flame atomic absorption spectrometry (FAAS) systems were evaluated for determination of As and Se in biological and environmental reference materials. Arsenic and Se hydrides are 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 limit was achieved compared with that obtained using anyone of the above atom trapping techniques separately. The concentration detection limits were 4 and 3 ng ml(-1) for As and Se, respectively. For a 2 min in situ preconcentration time, sensitivity enhancement, compared to FAAS, were 875 and 833 folds for As and Se, respectively, using hydride generation, atom trapping technique. The sensitivity can be further improved by increasing the collection time. The relative standard deviations (RSDs) are of the order of 5 - 9% for this hyphenated technique. The designs studied include slotted tube, water-cooled single silica tube and integrated atom trap. The accuracy was assessed by analyses of NRCC DOLT-2 (Dogfish Liver) and NIST SRM 1648 (Urban Particulate Matter) reference materials. The measured As and Se contents in two reference materials were in satisfactory agreement with the certified values.