Determination of nickel by chemical vapor generation in situ trapping flame AAS

Abstract

AbstractThe analytical performances of coupled chemical vapor generation, integrated atom trap (CVG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system were evaluated for determination of nickel in environmental samples. Nickel chemical vapors are atomized in an air-acetylene flame-heated IAT. A new design of CVG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangements (a water-cooled single silica tube, double-slotted quartz tube) permitting construction of an “integrated trap” was investigated. An improvement in limit of detection was achieved compared with that obtained using any of the above atom trapping techniques separately. The concentration limit of detection was 1 ng mL−1 for Ni. The overall efficiencies of the vapor generation process was estimated to be ca. 50%. For a 2 min in situ pre-concentration time, sensitivity enhancement, compared to FAAS, was 200 folds for Ni, using vapor generation atom trapping technique. The sensitivity can be further improved by increasing the collection time. The precision of the measurements for 25 ng mL−1 of Ni was 9% RSD. The accuracy of this method was tested by analyses of NIST SRM 2704 (Buffalo River Sediment), NIST SRM 1648 (Urban Particulate Matter), NIST SRM 2710 (Montana Soil), NBS SRM 1633a (Coal Fly Ash) and NIST SRM 1643e (Trace Element in Water) certified reference materials. The measured Ni content in five reference materials was in satisfactory agreement with the certified values (in the range of 14.3–98 μg g−1). The hyphenated technique was applied for nickel determination in coal fly ash, soil, sediment, sewage and river water.