A Versatile Carbon Fiber Cloth-supported Au Nanodendrite Sensor for Simultaneous Determination of Cu(II), Pb(II) and Hg(II)

A carbon fiber cloth (CFC)-supported Au nanodendrite (AuND@CFC) sensor was used to simultaneously measure the concentrations of Pb(II), Cu(II) and Hg(II) in real water samples. The sensor had a large electrochemically active surface area due to the hierarchical nanodendrite structure and the formation of the nanodendrite structure on the CFC was accomplished in just 5 minutes by single-step electrodeposition. After the optimization of important experimental conditions, such as pH and pre-concentration time, the achieved limit of detections (LODs) in the measurements of Pb(II), Cu(II) and Hg(II) were 0.15, 0.07, and 0.13ppb, respectively, which were superior and comparable to those reported in previous studies. The electrochemical responses of each analyte (concentration: 2.0ppb) were not influenced when the concentrations of interferants (Cr(IV), Ni(II), Mn(II), Zn(II), Al(III), Ca(II) and Mg(II)) were even 500-fold greater (1.0ppm); while only the signal of Cu(II) decreased when the Ni(II) concentration were 4.0ppm (2000-fold larger). When eight separately prepared AuND@CFC sensors were used to measure the samples, the relative standard deviations (RSDs) of the peak intensities of these metals were lower than 5.0%, thereby indicating the superior sensor-to-sensor reproducibility. When real river and lake water samples were analyzed, the determined concentrations were similar to those measured with ICP-MS and the recoveries ranged from 93.2%-118.7%. Overall, the proposed sensor is versatile enough to be incorporated into a portable analytical system for on-site detection of Pb(II), Cu(II) and Hg(II) in real field samples.