Article ID Journal Published Year Pages File Type
1233399 Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2010 5 Pages PDF
Abstract

A highly sensitive, selective and rapid method for the determination μg L−1 level of Au(III) based on the rapid reaction of Au(III) with 2,3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline (DCHNAQ) and the solid phase extraction of the colored complex with a reversed phase polymer-based C18 cartridge have been developed. The DCHNAQ reacted with Au(III) to form a violet complex of a molar ratio 3:1 [DCHNAQ to Au(III)] in the presence of 5.0 M of phosphoric acid solution and Triton X-100 medium. This complex was enriched by the solid phase extraction with a polymer-based C18 cartridge. The enrichment factor of 100 was achieved. The molar absorptivity of the complex is 2.73 × 105 l mol−1 cm−1 at 633 nm in the measured solution. The system obeys Beer's law in the range of 0.02–1.30 μg ml−1, whereas the optimum concentration ranges obtained from Ringbom plot was 0.08–1.24 μg ml−1. The relative standard deviation for ten replicates sample of 0.6 μg ml−1 level is 1.28%. The detection and quantification limits, are 6.1 and 19.5 ng ml−1 in the original sample. This method was applied to the determination of gold in water, jewel and ore samples with good results comparing to the GFAAS method.

Related Topics
Physical Sciences and Engineering Chemistry Analytical Chemistry
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