Development of a New and Highly Sensitive Method for Arsenic Determination in Drinking Water Samples Using Au-Coated W-Coil Atom Trap Hydride Generation Atomic Absorption Spectrometry

A novel ultra-sensitive gold-coated tungsten-coil atom trap coupled with HGAAS was developed for the first time for the determination of arsenic. The analytical methodology was based on transporting and in-situ trapping of arsine produced by the hydride generation system onto a gold-coated W-coil trap for preconcentration via Ar and H2 gases. The trap surface was examined using scanning electron microscopy and energy-dispersive X-ray spectroscopy. SEM images revealed that the surface is covered with hexagonal and pentagonal structures on a micro scale with gold. The experimental parameters were optimized for both trap and non-trap method. The enhancement factor for the characteristic concentration (C0) was determined to be 15.3 when compared with the non-trap methods. For the trapping time of 120 s using the developed method, the limit of detection (LOD) and the precision were determined as 4.8 ng L-1 and 3.6 %, respectively. The interference effects of various hydride-forming ions were examined in detail. The accuracy of this ultrasensitive methodology was successfully verified by analysis of certified reference materials and some drinking water samples.. t-test was implemented to the water samples, the added and measured concentrations exhibited no statistically meaningful distinction at the 95 % confidence level. This study presents a cost-effective, robust, selective, and ultra-sensitive methodology for the determination of arsenic in drinking water samples. The Au-coated W-coil is employed as an online trap before atomization in the QTA cell. All parameters affecting the analyte signal were optimized. The interference effects of other hydride-forming elements were also studied.image