Anodic Stripping Voltammetric Determination of Lead in Tap Water at an Ordered Mesoporous Carbon/Nafion Composite film Electrode

Abstract

Abstract A sensitive mercury‐free lead (Pb 2+ ) sensor has been proposed based on an ordered mesoporous carbon and Nafion composite film (OMC/Nafion) coated glassy carbon electrode. The analysis of Pb 2+ using anodic stripping voltammetry (ASV) includes two steps. Pb 2+ ions are firstly reduced and deposited on the electrode surface in a Pb 2+ solution (10 mL) during a preconcentration step biased at −1.0 V, followed by a measurement step by differential pulse voltammetry (DPV) within the potential range of −0.8 to −0.3 V (scan rate: 20 mV/s, frequency: 20 Hz, amplitude: 50 mV, pulse width: 50 ms). Linear calibration curve was found to be from 20 nM to 2 μM for Pb 2+ with a sensitivity of 17.4±1.38 μA/μM after a 5‐min of preconcentration. The detection limit was estimated to be around 4.60±0.12 nM at the signal to noise ratio of 3. Reproducibility ( RSD %) was found to be 3.0% for a single sensor with eight measurements and 4.3% for five sensors prepared with identical procedures. The practical application of the proposed lead sensor was verified by determination of trace level of Pb 2+ in tap water sample.