Minimization of Transition Metal Interferences with Hydride Generation Techniques

Abstract

A new hydride generator has been characterized for use with the acid-NaBH(4) hydride generation systems based on the insertion of a capillary tube into the sample introduction channel of a standard Meinhard nebulizer. The acidic sample and the tetrahydroborate solution are mixed at a merge point 1.5 cm from the end of the nebulizer orifice. Nebulization of the reaction solutions into a 0.7 mL tubular "spray chamber" follows a very short mixing time (less than 0.012 s) of the reagents. This approach permits 10 000 μg/mL Ni(2+) or Cr(3+) to be present in the sample solution without producing any interferences. Additionally, in the presence of Fe(3+) added as a "releasing agent", 5000 μg/mL Co(2+) or 160 μg/mL Cu(2+) can also be tolerated without interference. An 80 ± 2% generation efficiency is attained for the test element selenium. A detection limit of 6 μg/L (3σ(b)) is achieved with ICP-AES detection. Precision of replicate measurements at the 12 μg/L level varies from 5 to 12% relative standard deviation.

A Simple and Sensitive Flow-Injection On-line Preconcentration Coupled with Hydride Generation Atomic Fluorescence Spectrometry for the Determination of Ultra-trace Lead in Water, Wine, and Rice

“…28,29 One reason for this improvement is attributed to the advantages of FI on-line operation, i.e., minimizing the contact time between the lead hydride and the interfering species. 19,30 Another reason might be the use of NH3-NH4Cl as a precipitant, which would cause the analyte to be separated from the matrix, and would also mask some metal ions, such as Cu, Co, Zn and Ni, by forming the complexes. Elimination of the ethanol matrix effect.…”

Thin film hydride generation: determination of ultra-trace copper by flow injection in situ hydride trapping graphite furnace AAS

“…Sturgeon et al 21,22,[29][30][31] investigated several approaches based on a modified Meinhard nebulizer or Scott spray chamber to achieve rapid reactions and product separation from the liquid phase. Rapid mixing of the sample and reductant solutions by co-nebulizing 5 them permitted very short reaction times (below 100 ms) within the nebulizer assembly, leading to virtual suppression of interferences from transition and noble metals on the hydride generation of selenium.…”

Versatile Thin-Film Reactor for Photochemical Vapor Generation

“…The rapid separation provided by the thin film generator effectively minimizes such interferences. 21,22 …”

“…Sturgeon et al 21,22,[29][30][31] investigated several approaches based on a modified Meinhard nebulizer or Scott spray chamber to achieve rapid reactions and product separation from the liquid phase. Rapid mixing of the sample and reductant solutions by co-nebulizing them permitted very short reaction times (below 100 ms) within the nebulizer assembly, leading to virtual suppression of interferences from transition and noble metals on the hydride generation of selenium.…”