Highly sensitive determination of arsenic in water samples by hydrogen-doped solution anode glow discharge-optical emission spectrometry

Abstract

In this work, a new method based on hydrogen-doped solution anode glow discharge optical emission spectrometry (SAGD-OES) was developed for the direct detection of trace As in water samples. It was found that efficient vapor generation and excitation of As could be achieved simultaneously in the Ar–H₂ SAGD, contributing to the significant improvement in As signal sensitivity, compared to that in SAGD without doping of H₂ or solution cathode glow discharge (SCGD). As a result, it eliminates the use of a hydride generation (HG) sampling unit and only consumes low power (<10 W), enabling simple, rapid and sensitive detection of As. In addition, different from our previous work using He working gas for Sb analysis, sensitive detection of As in water is achieved with low cost Ar. Under the optimal operating conditions, the LOD for As was as low as 1.4 μg L⁻¹ (193.7 nm), and good linearity of the method was achieved in the range of 5–500 μg L⁻¹. It was found that the coexisting ions could suppress the As signal significantly. Fortunately, the severe interference could be readily solved by using cation exchange resin to rapidly remove the concomitant cations. Finally, the accuracy of the proposed method was validated by the analysis of a certified reference material [GSB 07-3171-2014] and real water samples. The proposed low power, green, and simple method provides a promising approach for sensitive and rapid field As analysis.