Cai Ya-qi

Plasma degradation of Cationic Blue dye with contact glow discharge electrolysis

Contact glow discharge electrolysis (CGDE) of Cationic Blue SD-GTL (CB) was investigated by determining degradation rates and rate constants under different voltages, pH, temperature and initial concentrations. The results indicated that 500 V was the optimum voltage for CGDE of CB under experimental conditions. The effect of pH was not appreciable. Fe²(+) and Fe³(+) had a remarkable catalytic effect on the degradation of CB. The degradation rate was up to 99.7% after 3 minutes CGDE treatment when the concentration of Fe²(+) was 20.0 mg/L. And when the concentration of Fe³ (+) was 5.0 mg/L, the degradation rate was only 68.6% after 10 minutes CGDE treatment. The reaction mechanisms were also well illustrated by relative reactions and their rate constants. It had been demonstrated that CB underwent oxidative degradation in CGDE.

Advances on environmental mass spectrometry for emerging contaminants

With the rapid development of instrument science and technology, mass spectrometry and its hyphenation technique is being used pervasively in environmental analysis at such a unprecedened speed, scale and depth. Their application in environmental monitoring has been or is being become the work practices of the day-to-day. In recent years, some high resolution mass spectrometry and their hyphenation with chromatography, especially high resolution chromatography, have played a more and more important role in accurate determination of targeted emerging contaminants and nontarget screening analysis of their metabolites and transformation products, which is vital to elucidate the environmental fate of emerging contaminants. This paper summarized the advances on the study of environmental mass spectrometry and their hyphenation technique with gas chromatography and liquid chromatography for the analysis of emerging contaminants, and the great concern about application of the high resolution mass spectrometry in environmental analysis was emphasized. The future developing perspectives were also presented.

Determination of Trace Iodide in Saturated Brine Using Ion Chromatography

Abstract A new method was developed for the determination of iodide in saturated brine after in-line pretreatment by ion chromatography with pulsed amperometric detection. IonPac Cryptand C1 column was used to concentrate iodide in saturated brine sample, which was subsequently rinsed with 10 mM NaOH to remove interfering chloride. Third, NaOH at 0.5 mM concentration was used to elute iodide from the concentrator column and refocus it on the head of the AG20 guard column. The separation of iodide was achieved on an IonPac AS20 column with 25 mM NaOH as eluent. The detection limit of iodide was 0.07 μg l−1 (50 μl injection, signal-to-noise ratio of 3) and the linear range of the calibration curve of peak height vs analyte concentration was from 5.0 to 1000 μg l−1. The relative standard deviation (RSD) of the peak height for 50 μg l−1 iodide was 1.0% (n = 9).