Sensitive and Environmentally Friendly Field Analysis of Waterborne Arsenic by Electrochemical Hydride Generation Microplasma Optical Emission Spectrometry

To avoid polluting the environment, it is desirable to develop methods consuming as few chemicals as possible for field elemental analysis. In this work, a lithium-ion battery supplied, compact handheld optical emission spectrometer (OES) (0.3 kg, length 18 cm × width 5 cm × height 10 cm) was fabricated for the sensitive field analysis of waterborne arsenic by utilizing electrochemical hydride generation (ECHG) and miniaturized ballpoint discharge (μPD) as sample introduction means and excitation source, respectively. The high ECHG efficiency of arsenic was obtained using a superior cathode of Fe@PbO/Pb and the generated arsine was separated from an aqueous phase and further swept to the μPD microplasma for detection. It is worth noting that the Fe@PbO/Pb cathode not only retains advantages of large specific surface area, robust stability, and excellent reproducibility for the ECHG of arsenic but also accomplishes the preconcentration of As(III), thus improving the kinetics of the surface chemistry at the cathode, alleviating the corrosion of the electrode, and minimizing the release of Pb. A limit of detection of 1.0 μg L-1 was obtained with a relative standard deviation of 4.2% for 20 μg L-1 As(III). Owing to the advantages of ECHG and μPD-OES, the system retains a promising potential for the sensitive, cost-effective, and environmentally friendly field analysis of waterborne arsenic.