Miniaturized Corona Discharge-Atomic Emission Spectrometer for Determination of Trace Mercury / 分析化学

ABSTRACT

A miniaturized atomic emission spectrometer composed of a corona discharge source and a handheld charge-coupled device detector was constructed for the sensitive determination of trace mercury, with photochemical vapor generation for sample introduction. By using formic acid, mercury vapor was generated under the irradiation of UV light, and then the vapor was introduced into the corona discharge area with the carrier gas flow of argon. The optical signals were captured and analyzed by the charge-coupled device detector at 253. 7 nm. Under the optimized conditions including 4% formic acid, discharge voltage of 90 V, and carrier gas flow rate of 200 mL/min, the stable detection signals were obtained ( RSD=2. 5%). The calibration curves were plotted with the concentration of mercury ranging from 0. 5 to 1000 ng/mL, with a correlation coefficient >0. 99 and the limit of detection of 0. 03 ng/mL. Two certified reference materials were analyzed, and a t-test demonstrated that the determined results by the proposed method had no significant difference with the certified values at the confidence level of 95%. Water samples collected from both Funan River in Chengdu and the Lotus Pond on campus of Sichuan University were analyzed as well, with the recoveries of standard addition between 93 . 8% and 103%. The miniaturized instrumentation demonstrated several advantages including easy construction, low power consumption, high sensitivity, and portability for field analysis.