Voltammetry Was Used To Determine Nitrate, Lead And Copper Ions In PM2.5

PM2.5, especially the particles with the aerodynamic diameter less than 2.5?m, is the primary pollutant of atmospheric environment of our country now. It exceeds standard seriously in many large and medium-sized cities of our country. Now, this situation has attached great attention by domestic and foreign governments and research departments. In this paper, different materials modified electrodes have been applied to detect different solubale ions in PM2.5 The major research contents of this paper are as follows.Part 1 Stripping voltammetry determination of nitrate ions in PM2.5In this paper, the determination of nitrate ions in PM 2.5 samples with porous copper modified electrode was investigated. The research studied not only the electrochemical properties of nitrate ions with the porous copper modified electrode but also the relationship between the response current and the concentration of nitrate ions. The peak currents were linear in concentration range of nitrate from 6.67×10-6 to 2.00×10-4 mol/L with the correlation coefficient r of 0.998, and the detection limit was 2.00×10-6 mol/L. This method can be used for detecting the concentration of nitrate ions in PM2.5 samples and the results were correlated with that obtained by chromatography method. This indicates that the method can be a reliable solution to detect the content of nitrate ions in PM 2.5 samples with electrochemical measurementPart 2 Stripping voltammetry determination of lead ions in PM2.5In this study, Polyglycine was electrochemically deposited on MWCNT/Nafion modified electrode to detect Pb2+ in PM2.5. The electrochemical behavior of lead ions on the electrode surface was studied by stripping voltammetry. Various operational parameters such as deposition potential, deposition time and speed rate were optimized. Lead ions emerge a sensitive oxidation peak at -550 mV. The linear calibration curves ranged from 3.00×10-8?1.00×10-5 mol/L for individual analysis showed a good linear relationship. Polyglycine-MWCNT/Nafion can be selected as the better material to prepare modified carbon electrode for Pb2+ determination in PM2.5.Part3 Stripping voltammetry determination of lead ions and copper ions in PM2.5In this study, dithizone was modified on the surface of carbon electrodes to detect Pb2+ and Cu2+ in PM 2.5. The modified glassy carbon electrode was compared with bare glassy carbon electrode with higher response sensitivity. The electrochemical behavior of Pb2+ and Cu2+ on the modified electrode was studied using stripping voltammetry. Various operational parameters such as deposition potential, deposition time and speed rate were optimized. The detections were performed in B-R buffer solution (pH=3) in the potential range of -900?200 mV at the scan rate of 100 mV/s. The peak potentials of Cu2+ and Pb2+ were at -0.08 V and -0.48 V, respectively. The linear regression equation for lead is I(?A)=2.70958 X 10"7+0.08419 C in the concentration range from 3.0×10-8 to 1.0×10-5 mol/L and the correlation coefficient is 0.987. Two linear ranges are obtaind for copper ions. The first part for copper is I(?A)=2.58723 X 10'6+0.2863 C in the concentration range from 7.0 ×10-12 to 7.0 × 10-10 mol/L and the correlation coefficient is 0.998. The second part is I (?A)=4.87923 ×10-6+4.30155C in the concentration range from 5.0× 10-9 to 1.0 ×10-6 mol/L and the correlation coefficient is 0.997. A new method for the determinations of trace amounts of lead and copper from PM 2.5 was obtained. This method has been applied to the determination of Pb2+ and Cu2+ in PM 2.5 samples, and the results are satisfactory.