A portable instrument for on-site detection of heavy metal ions in water.

Based on differential pulse voltammetry technology, we developed a portable and affordable instrument for on-site detection of trace heavy metal pollutants in liquid through a disposable plastic pipette. It mainly consists of a six-electrode electrochemical sensor which is integrated in the instrument. The pipette chip is equipped with a pump valve, and thus, it can avoid contamination. We have analyzed the sensitivity and specificity of the electrochemical sensor for heavy metal detection. Experimental results demonstrated that the limit of detection for Pb, Hg, Cu, and Zn was 2.2 ng/mL, 2.5 ng/mL, 15.5 ng/mL, and 10 ng/mL, respectively. The limit of quantification for them was 10 ng/mL, 25 ng/mL, 25 ng/mL, and 14 ng/mL, respectively. The correlation coefficient between peak current and the target heavy metal concentration was above 0.96. Finally, we have tested the analytical performance of the self-build instrument by measuring heavy metal ions in industrial wastewater and rainwater, respectively. Such an instrument is user-friendly for all users even for the common people, and we can envision its wide application in future heavy metal pollutant detection in groundwater, tap water, and supernatant of soil solution. [ABSTRACT FROM AUTHOR]