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Studies on the Adsorptive Stripping Voltammetry of Copper (Ⅱ) and Lead (Ⅱ) at Chemically Modified Carbon Paste Electrodes Cotaining Morin or Quercetin

Author: FeiJunJie
Tutor: LiJuNan
School: Xiangtan University
Course: Analytical Chemistry
Keywords: Copper Lead Morin Quercetin Chemically modified carbon paste electrode Adsorptive stripping voltammetry
CLC: O657.1
Type: Master's thesis
Year: 2001
Downloads: 265
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Abstract

This paper examined a large amount of literature on the basis of the first successful production of morin (Mor) and quercetin (Qu) modifier chemical modified carbon paste electrode. And two new electrode as the working electrode determination of trace amounts of copper and lead by adsorptive stripping voltammetry. The text is divided into four chapters: the first chapter of copper (II) modified carbon paste electrode by adsorptive stripping voltammetry at the Morin chemical behavior. Mixing enrichment in 0.06 mol / L formate buffer solution (pH 4.6), 0.20 V (vs. SCE), copper (II) and chemically modified carbon paste electrode surface Morin electrically active complex adsorption enriched in the surface of the electrode at -0.45 V at the standing restore anodized linear sweep, a sensitive copper stripping peak around -0.05 V in different accumulation time, the second derivative of the peak current and the copper (II ) concentration showed a good linear relationship in the range of 1.0 × 10-9 ~ 6.0 × 10-8 mol / L and 2.0 × 10-8 to 9.0 × 10-7 mol / L with a detection limit of 4.0 × 10 -10 mol / L. 10 repeated measurements, the RSD was 4.32%. The same electrode surface can be tested 20 times. Use carbon paste electrode, etc. Continuous variation of complex composition ratio of 1:1. Explore the mechanism of electrode reaction. The method is applied to human hair in the determination of trace copper, obtained satisfactory results. Chapter II of lead (II) in the Morin chemical modified carbon paste electrode by adsorptive stripping voltammetry. Under the best conditions, lead (II) by anodic stripping peak at about -0.43 V, the second derivative peak current and the concentration of lead (II) in 5.0 × 10-9 ~ 1.0 × 10-7mol / L and 2.0 × 10-8 ~ 1.0 × 10-6 mol / L showed a good linear relationship between the two ranges, the detection limit was 1.0 × 10-9 mol / L. Use carbon paste electrode, etc. Continuous variation of complex composition ratio of 1:1. Explore the mechanism of electrode reaction. The method has been successfully applied to the determination of lead in urine. The Chapter reported carbon paste electrode modified with quercetin chemical adsorptive stripping voltammetry determination of trace copper (II). Reduction (-0.40 V) after anodic dissolution of a sensitive stripping peak around -0.03 V (0.20 V) enriched in 0.08 mol / L formate buffer solution (pH 4.7). Peak current and the concentration of copper (II) in 1.5 × 10-9 to 8.0 × 10-8 mol / L lt; WP = 18 GT; was 1.5 × 10-8 ~ 9.0 × 10-7 mol / L within the good linear relationship between the detection limit of 8.0 × 10 -10 mol / L. 10 repeated measurements, the RSD was 3.85%. Explore the mechanism of the electrode reaction and the composition ratio of the complex was measured. The method was applied to the determination of trace copper in human serum with satisfactory results. Chapter IV presents the application quercetin chemically modified carbon paste electrode determination of trace lead (II) by adsorptive stripping voltammetry. Single factor variation method to obtain the optimal experimental conditions: electrode of quercetin and liquid paraffin content of 1% and 22%, respectively; enrichment and dissolution medium of 0.10 mol / L sodium formate slow solution (pH 4.3); rich set potential to -0.10 V, the level of concentration enrichment time for the 150s and 300 s; reduction potential to -0.70 V, the restore time is 40 s. Dissolution peak at about -0.42 V. Peak current and the concentration of lead (II) in 2.0 × 10-9 ~ 6.0 × 10-8 mol / L and 1.0 × 10-8 to 8.0 × 10-7 mol / L range of two showed a good linear relationship between detection limit of 8.0 × 10-10 mol / L. Discussed in detail the mechanism of electrode reaction and verify the composition ratio of the complex. The method is applied to the determination of trace amounts of lead (II) in water samples, and achieved satisfactory results. In summary, through in-depth, systematic test preparation morin and quercetin chemically modified carbon paste electrode, and the use of these electrodes, the establishment of new adsorptive stripping voltammetry determination of trace amounts of copper (II), Pb (II) Methods. The method has high sensitivity, selectivity, good reproducibility. New voltammetric sensor has a certain theoretical and practical value.

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