Rapid and Portable Detection of Pb(II) and Cd(II) Ions Using a Screen-Printed Graphene Electrode Enhanced with Alkalized MXene and Gold Nanoparticles

This study introduces the development of a portable electrochemical sensor for the detection of Pb(II) and Cd(II) ions based on a screen-printed graphene electrode (SPGE) enhanced with alkalized MXene and gold nanoparticles (AuNPs). Experimental results reveal that the Au@Alk-MXene/SPGE electrode exhibits excellent electrical conductivity, enlarged active surface area, and efficient electron transfer capability, which enhances the electrochemical detection of Pb(II) and Cd(II) ions. Under optimal experimental conditions, the sensor demonstrates good electrochemical response and distinct stripping peaks for both ions. The linear detection range of the sensor is 5-130 μg L⁻¹ for both Pb(II) and Cd(II), with detection limits of 0.198 μg L⁻¹ for Pb(II) and 0.106 μg L⁻¹ for Cd(II). Furthermore, the sensor shows excellent repeatability with relative standard deviations (RSDs) of 1.16% (n = 10) for Pb(II) and 1.25% (n = 10) for Cd(II), as well as remarkable reproducibility with RSD values of 1.56% for Pb(II) and 1.57% for Cd(II). The sensor was successfully applied to analyze tap water and lake water samples, demonstrating satisfactory recovery rates. This research shows the use of MXenes and AuNPs to modify SPGE electrodes, offering a rapid and portable electrochemical sensor for detecting Pb(II) and Cd(II) ions in water.