IMPEDIMETRIC Au-NTA SENSOR FOR LEAD DETERMINATION Marina Palcic1, Irena Kerkovic2, S. Milardovic2 and Zorana Grabaric1 1University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10 000 Zagreb, Croatia 2University of Zagreb, Faculty of Chemical Engineering and Technology, Marulicev trg 19, 10 000 Zagreb, Croatia Summary A self assembled monolayer (SAM) of cysteamine was prepared on the surface of gold disc electrode and further modified with nitrilotriacetic acid (NTA). surface characterization was performed by cyclic Sensor’s voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in the presence of potassium hexacyanoferrate (II)/(III) redox pair. Complexation of NTA with Pb2+ was tested by EIS measurements using the same redox pair as in the surface characterization. Electrode response was linearly proportional to log with correlation c(Pb2+) (log ∆Rct) coefficient R2 = 0.9865 for measurements in buffer pH = 4.60 and R2 = 0.9931 for pH = 7.06 in the concentration range of 0.06-66 µmol/L. Keywords: impedimetric sensor, lead, NTA, self assembled monolayers
IMPEDIMETRIC Au-NTA SENSOR FOR LEAD DETERMINATION Marina Palcic1, Irena Kerkovic2, S. Milardovic2 and Zorana Grabaric1 1University of Zagreb, Faculty of Food Technology and Biotechnology, Pierottijeva 6, 10 000 Zagreb, Croatia 2University of Zagreb, Faculty of Chemical Engineering and Technology, Marulicev trg 19, 10 000 Zagreb, Croatia Summary A self assembled monolayer (SAM) of cysteamine was prepared on the surface of gold disc electrode and further modified with nitrilotriacetic acid (NTA). Sensor’s surface characterization was performed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in the presence of potassium hexacyanoferrate (II)/(III) redox pair. Complexation of NTA with Pb2+ was tested by EIS measurements using the same redox pair as in the surface characterization. Electrode response (log ∆Rct) was linearly proportional to log c(Pb2+) with correlation coefficient R2 = 0.9865 for measurements in buffer pH = 4.60 and R2 = 0.9931 for pH = 7.06 in the concentration range of 0.06-66 µmol/L. Keywords: impedimetric sensor, lead, NTA, self assembled monolayers