| Abstract [eng] |
In this work the gallium and bismuth film plating in situ and ex situ processes were investigated. The metal film plating conditions for determination of heavy metals in water samples were optimized. When depositing Bi films on glassy carbon electrode it was found, that the addition of Br-1 changes the BiFE morphology making it more uniform and forming crystalline aggregates. The reoxidation peak of Bi was shifted to more negative potentials showing the electrocatalytic effect of bromide for the bismuth film. The addition of the other metal ions to the deposition solutions caused changes in the morphology of the Bi film It has been shown, that Cd was slowing the Bi film deposition and Pb was catalyzing this deposition. Zn(II), Cd(II), Cu(II) and Pb(II) ions were determined in the water samples using bismuth film electrode. The linear calibration curve of each metal was obtained. Good linear responses of the peak area vs. concentration were obtained for Zn(II), Cd(II), Pb(II) and Cu (II) with correlation coefficients of 0.997, 0.997, 0.999 and 0.998 respectively. The possibilities of gallium film plating were studied. The glassy carbon substrate was chosen for optimization. The optimized deposition conditions were: supporting electrolyte 0.1 M acetate buffer, deposition potential -1.7 V, deposition time 120 s, deposition temperature 40oC. The gallium influence on Pb(II) and Cd(II) deposition at the glassy carbon electrode was studied. It has been shown that Pb(II) and Cd(II) peaks increased significantly in the presence of 1 mg L-1 gallium when deposited in situ. The possibilities to determine Zn(II) on gallium film electrode using different carbon substrates were studied. It has been shown that gallium film plated in situ and preferably onto the carbon paste-based support can be used in anodic stripping voltammetry for zinc(II) determination (in an interval of 10-50 µM Zn(II)). |
