NGHIÊN CỨU PHÁT TRIỂN ĐIỆN CỰC MÀNG BISMUT IN SITU CHO PHƯƠNG PHÁP VON-AMPE HÒA TAN HẤP PHỤ SÓNG VUÔNG XÁC ĐỊNH LƯỢNG VẾT CADIMI VÀ CHÌ

Tóm tắt

Bismuth film electrode prepared in situ on glassy carbon disk surface (abbreviated to BiFE in situ) wasused as working electorode for square-wave adsorption stripping voltammetry (SqW-AdSV) for thedetermination of cadmium (Cd) and lead (Pb) in HEPES buffer (pH  7.3) and the presence of calceiblue (CB) as a complexing ligand. The influence of the factors on Cd and Pb stripping peak curent (Ip)such as: BiIII concentration, HEPES and CB concentrations, deposition potential and deposition time,adsorptive potential and adsorptive time, the electrode rotating speed, interferents… wereinvestigated. At the deposition potential of -1500 mV, the deposition time of 90 s and the adsorptivepotential of -400 mV, the adsorbent time of 1 s, the method gained high sensitivity (116 ± 6 and 105 ± 5nA/ppb for Cd and Pb, respectively), good reproducibility of the Ip : RSD = 9% and 2% (n  9) for Cdand Pb, respectively, low detection limit (3) (1.4 – 1.6 ppb for each metal); linear correlation bewteenthe Ip and the metal concentration was good in the range of 2 – 50 ppb (R ≥ 0,99).