Detection Of Trace Environmental Pollutant With Poly (aromatic Diamine) Modified Glassy Carbon Electrode

Polydiaminonaphthalene is a new type of conducting polymer withπ-bond following polyaniline, polypyrrole and polythiophene, which has many more new functions due to a large number of amino groups and imido groups, and it can form complexes with several heavy metal ions. This characteristic makes it possible for the electrodes to concentrate and detect the heavy metal ions in dilute solutions when polydiaminonaphthalene is modified on electrodes. This paper introduced the prepararation and application of polydiaminonaphthalene modified electrode according to the latest literature. Based on the highly adsorption charicteristic of poly(1,8-diaminonaphthalene), methods for the separate determination of trace Hg2+, Ag+, Cu2+ and the simultaneous determination of trace Cu2+ and Hg2+ in water sample were established.In this paper, poly(1,8-diaminonaphthalene) modified glassy carbon electrode was prepared by cyclic voltammetry. It discussed parameters of electropolymerization, such as reaction medium, scan potential, scan rate, scan time and so on, the electrochemical behavior of the polymer was also researched. Hg2+, Ag+, Cu2+ were firstly accumulated on the modified electrode, then the accumulated mercury, silver and copper were anodically stripped by differential pulse voltammetry separately. The volt-ampere characteristics of Hg2+, Ag+, Cu2+ were studied. Different parameters, such as the pH and concentration of the accumulating solution, preconcentration time were studied, the scan potential, rest potential, rest time, scan rate and so on were optimized when it was anodic stripping. It also studied the interference of other ions. In addition, the electrochemical reaction mechanism of the metal ions on the modified glassy carbon electrode were discussed preliminary.The conclusions of the experiment were as follows: at the optimum experiment condition, when anodically stripped by differential pulse voltammetry, a well-defined anodic peak of mercury was at +0.07V, the linear ranges were 0.001~0.1 mgL-1 and 0.1~5mgL-1 with a detection limit of 0.0005mgL-1; a well-defined anodic peak of silver was at 0.0V, the linear range was 0.0008~0.1mgL-1 with a detection limit of 0.0005 mgL-1; two anodic peaks of copper could be observed at -0.25V and +0.40V, the linear ranges were 0.0008~0.1 mgL-1 and 0.1~2 mgL-1 with a detection limit of 0.0005 mgL-1. When it was used for the simultaneous determination of trace Cu2+ and Hg2+, the linear range of copper was 0.001~0.2mgL-1, the detection limit was 0.0008mgL-1; the linear range of mercury was 0.002~1mgL-1, the detection limit was 0.001mgL-1.This method is easy, fast, anti-interference, the detector is having good selectivity, high sensitivity as well as low detection limit, the results were satisfied when it was used to detect trace Hg2+, Ag+ and Cu2+ in water sample, it can be regarded as an new alternative to the conventional method, the future high perfermance of these electrodes as potential detecting electrodes and sensors are foresee.