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

Abstract

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.

Nozzle Electrode Point Discharge-Enhanced Oxidation and Portable Gas Phase Molecular Fluorescence Spectrometry for Sensitive Field Detection of Sulfide

“…As expected, the concentration of sulfite obtained by NEPD was much higher than those achieved by the other three oxidation methods (Figure c). These results fully confirm our hypothesis that NEPD is the most ideal oxidation method for H 2 S. Inspired by previous work, − this excellent oxidation is attributed to the fact that the nozzle electrode can confine the analyte species in the nozzle and introduce the analyte species into the interior of the large microplasma zone and diffuse analyte from the interior to the exterior of the plasma, leading to an oxidation efficiency higher than that of the TEPD. Moreover, the gas entered the discharge zone in a high-speed jet with better dispersion, which results in sufficient collision reactions between oxidizing species and H 2 S; thus, a higher signal intensity was obtained.…”

“…This was probably because the hollow electrode was ablated and oxidized by the discharge, and then the surface of the electrode tips became rough or generated metal oxides. Therefore, despite the growing interest in the application of μPD-OES, − there are still no reports on the use of HEPD for the effective oxidation of gaseous compounds.…”

“…Furthermore, the commercial atomic fluorescence spectrometer was bulky, highly energy-consuming, and heavy, thus limiting its application in real-time field analytical chemistry. Recently, a hollow metal electrode point discharge (HEPD) was developed as a novel excitation source for microplasma optical emission spectrometry (OES). − Unlike the conventional tapered tungsten electrode point discharge (TEPD), volatile analytes could be confined in the hollow electrode and almost completely transported into the microplasma region with HEPD, thus significantly enhancing sample introduction and excitation efficiency as well as subsequently improving the analytical performance of microplasma OES. However, this point discharge could not be maintained for a long time and then quickly turned into a filamentary discharge.…”

Battery-Operated and Self-Heating Solid-Phase Microextraction Device for Field Detection and Long-Term Preservation of Mercury in Soil

“…Moreover, the continuum background obtained by headspace sampling is unstable and significantly increases compared to that obtained by the self-heated HS-SPME. According to the results reported in previous work, the phenomenon from headspace sampling is caused by the fact that hydrogen produced by the reaction of NaBH 4 and HCl is also swept into the μPD-OES chamber as well. These results indicate that the proposed method not only retains the advantages of conventional HS-SPME coupling with alkylation, such as the efficient separation of analyte from matrix and other reaction products and the preconcentration of analyte, but also significantly reduces analysis cost, suggesting that the method is the most ideal sampling method for MP-OES.…”

Selenium in Photochemical Vapor Generation: Mechanism Study and Potential Nonchromatographic Speciation Analysis

“…In analytical chemistry, generation of volatile species has been widely used to enhance sample introduction, especially for atomic spectrometry such as inductively coupled plasma mass spectrometry (ICPMS), optical emission spectrometry (ICP-OES), atomic absorption spectrometry (AAS), and atomic fluorescence spectrometry (AFS), yielding high transport efficiency and efficient matrix separation through different derivatization strategies of chemical, , electrochemical, sonochemical, etc. , Compared with other strategies, photochemical vapor generation (PVG) , assisted by ultraviolet (UV) radiation owns lots of comparative advantages, including less reagent consumption and waste production, minimized interference from transition metals, improved stability of plasma (low hydrogen generation), etc. − …”