Inkjet Printed Multi‐walled Carbon Nanotube Sensor for the Detection of Lead in Drinking Water

Electroanalytical methods can be used for the reliable detection of the toxic heavy metal lead in drinking water samples. Inkjet printed electrodes have potential for the rapid and affordable assessment of drinking water. Researchers have shown the electrochemical sensing applicability of inkjet printed electrodes. In this work, Pb²⁺ was detected using an inkjet printed multi‐walled carbon nanotube (IJP‐MW‐CNT) electrode with silver tracks printed underneath. The silver tracks provide the sensor with the conductivity needed for sensitive measurements. MW‐CNT were dispersed in water using bile salts as a surfactant to prepare the ink. The IJP‐MW‐CNT electrode was used as the working electrode with a platinum wire and Ag/AgCl as auxiliary and reference electrode, respectively. The electrodes performance was optimized in 0.1 M acetate buffer (pH=4.3) and had two linear ranges of 5 to 20 ppb (R²=0.99) with a sensitivity of 38 nA/ppb and 20 to 50 ppb (R²=0.98) with a sensitivity of 15 nA/ppb and a limit of detection (LOD) of 1.0 ppb for Pb²⁺. The analytical applicability of electrode was determined by constructing a calibration curve in an unaltered drinking water sample (i. e.) Cincinnati tap water with two linear ranges of 15 to 40 ppb (R²=0.99) with a sensitivity of 1.5 nA/ppb and 40 to 70 ppb (R²=0.99) with a sensitivity of 3.5 nA/ppb and a LOD of 1.0 ppb for Pb²⁺. Effects of copper and cadmium as potential interferents are reported.