Abstract
An electrochemical anodic stripping voltammetry (ASV) coupled with auto-pretreatment system (Auto-Pret system) as an automated flow system was applied for trace metal analysis. A micro-flow sensor consisted of preconcentration membrane and three-eletrode electrochemical part was used as a detector. The characterization of the carbon electrode in micro-flow sensor such as life time, reproducibility and sensitivity were performed. The micro-flow sensor was tested with 50 ppb of Cd(II) and Pb(II) in 1.0 M HCl, as a supporting electrolyte, by on-line differential pulse anodic stripping voltammetry. It was used for 160 samples with the relative standard deviation less than 10 %. Analytical parameters for quantitative determination of Cd(II) and Pb(II) were investigated by differential pulse anodic stripping voltammetry (DPASV) and square-wave anodic stripping voltammetry (SWASV). Detection limits were 2.37 ppb and 0.15 ppb for the determination of Cd(II) and Pb(II) by DPASV and 0.02 ppb and 0.01 ppb for the determination of Cd(II) and Pb(II) by SWASV. The relative standard deviation less than 8 % for Cd(II) and less than 5 % for Pb(II) were achieved with each 50 ppb of metal ion solution. The results indicated that the carbon electrode in micro-flow sensor coupled with on-line Auto-Pret system have a good efficiency for the metal ion determination.
