Chitosan Modified Boron-doped Diamond Thin-film Electrode For Determination Of Copper Ion

As new semiconducting film materials, BDD thin-film is now in widespread use. In my experiments, I emphatically study the electrochemical behavior of Cu²⁺ by BDD thin-film electrode. At the same time, a method has been developed to measure the content of HPO2-4 by BDD thin-film electrode that is modified by chitosan, The BDD thin-film electrode has a better electrochenmical stability, a wide potential window, and a very low background current and a good stain release capability. A suitable modified material can improve sensitivity and selectivity of electrode.With tantalum as substrate and diboron trioxide as boron source, boron-doped diamond thin-film was prepared by hot filament chemical vapor deposition technique. Chitosan was used to modify BDD thin-film electrode by the method of covalent-band reaction and used in the determination of Cu²⁺ in the Na₂HPO₄ buffer solution(0.1mol/L, PH=4). The results showed that a good linear range for Cu²⁺ was from 4.0×10^-7 to 1.0×10^-3. The detection limit was 7.0×10^-8 mol/L and correlation coefficient was 0.9916. Comparing the test results of Cu²⁺ by different enrichment mode. While use the unmodified electrode and chitosan modified electrode to detect the same concentration of copper ions, the reductive peak current increased and reductive potential changed. It showed that the chemically modified BDD thin-film electrode can detect Cu²⁺ sensitively and accurately. Besides, it proved that chitosan had been modified successfully on BDD thin-film electrode.In addition, chitosan was used to modify BDD thin-film electrode by the method of covalent-band reaction and used in the determination of HPO₄^2- in the NaCl buffer solution(0.1mol/L, PH=7). This shows that BDD thin-film electrode can detect some anions and some cationics well.