The limit of detection of Cu was improved from 0.217 mg/L to 0.092 mg/L by acquiring spectra only in 25–100 μs, under the optimal conditions. The interferences of spectral line of Cu I (324.8 nm) are mainly sourced by the spectral bands of N 2 (C-B) and OH (A-X), which could be reduced by the temporal resolved spectra. It was found that the optimal detection sensitivity of Cu are obtained under the conditions of HNO 3 solution with 1.0 pH value, 3.0 mL/min solution flow rate, 8.5 kV pulse peak voltage, and 100 μs pulse width. The spatiotemporal distributions of gas temperature and electron density were calculated by the rotational temperature of OH (A) and the Stark broadening of H β (486.1 nm), respectively. The spatiotemporal resolved spectra of Cu I (324.8 nm), OH (A 2Σ–X 2Π) and N 2 (C 3Π u–B 3Π g) were diagnosed. The waveforms of voltage and current, as well as optical emission spectra of discharge were investigated, and the experimental conditions were optimized. In this paper, a novel microsecond pulsed electrolyte cathode discharge was generated and coupled with temporal resolved atomic emission spectra to analyze Cu element, as one of the representative heavy metals. Atmospheric pressure electrolyte cathode discharge plasma presents a great potential on detecting heavy metal pollutants.
0 kommentar(er)
