Electrochemical detection of chloride ions using Ag-based electrodes obtained from compact disc

In this work electrochemical sensors fabricated from compact disc material (waste or new) are used to quantify chloride ions in different types of samples. All three electrodes, working, counter, and pseudo-reference electrodes, were fabricated from the compact disc and directly used. Different parameters were studied in order to demonstrate the possibility of using this waste material for efficient and low-cost electrochemical sensors. Chloride sensing performance was evaluated using linear scan voltammetry as the detection technique. A sensitivity of 0.174 mA mM^-1 cm^-2 with a limit of detection of 20 μM and excellent selectivity against many interferents was observed. Selectivity and reproducibility tests were also carried out, showing excellent results. Sensors were also validated with real samples (drinking and sea water, milk, sweat and physiological solutions) with results comparable to conventional techniques. Our results show the applicability and suitability of these low-cost sensors, for detection of those analytes for which, silver, has high sensitivity and selectivity.

Tracking motion trajectories of individual nanoparticles using time-resolved current traces

We report experiments and simulations demonstrating that multiple distinct motion trajectories of individual nanoparticles can be discerned from time-resolved current traces.

Single nanoparticle (NP) electrochemical measurements are widely described, both theoretically and experimentally, as they enable visualization of the electrochemical signal of a single NP that is masked in ensemble measurements. However, investigating the behavior of individual NPs using electrochemical signals remains a significant challenge. Here we report experiments and simulations demonstrating that multiple distinct motion trajectories could be discerned from time-resolved current traces by dynamic Monte Carlo simulations. We show that continuous monitoring and quantification of electrochemical oxidation of individual AgNPs using a low-noise electrochemical measurement platform produce significantly distinguished current traces due to the size-dependent motions of AgNPs. Our findings offer a view of the electrochemical signals of individual NPs that are largely different from that in the literature, and underscore the significance of motion behaviors in single NP electrochemistry.