entity electrochemistry based on measurements of collision events at electrode surfaces is a rapidly developing field which provides extensive capabilities for detection and characterization of a variety of materials including organic and inorganic nanoparticles (NPs) and nanostructures as well as biologicals. The method has demonstrated promising potential for the analysis of catalytic activity, physicochemical parameters, fundamental surface properties, functionalization and reactivity of NPs. Here, the most recent developments and capabilities of this method as a novel tool for characterizing nanoscale properties are discussed, illustrating novel applications for assessing bioconjugation, designing ultrasensitive biosensing methods and monitoring processes of biological and environmental significance. The main advantages and limitations as compared to commonly used spectroscopy and imaging techniques are described, highlighting areas in which collision measurements can be used as a complementary approach to characterize properties of inorganic NPs, organic molecules, soft materials and biologicals, and develop methodologies for detection and quantification of analytes of interest in the bioanalytical, biological and environmental fields. An overview of potential applications in these fields is provided along with a critical discussion of future research needs and opportunities.

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This work describes a rapid easy‐to‐use electrochemical method for quantifying lead (Pb2+) adsorption on metal oxide nanoparticles (NPs), demonstrated here for titanium dioxide (TiO2). The method was able to quantify Pb2+ adsorption for concentrations as low as 0.95 μM, and up to 200 μM in NP dispersions, and to differentiate ion uptake in the presence and absence of a natural organic material, humic acid (HA). The method was selective for Pb2+ against Cu2+, As3+, Zn2+, Cd2+ and Cr3+ ions when measured in the specific potential range from −0.4 to −0.6 V and was successfully demonstrated in water and home‐collected dust.

A graphite paste electrode (GPE) modified with chemically synthesized Polythiophene nanostructures (PTh) was proposed for simultaneous voltammetric detection of Dopamine (DA), Uric acid (UA) and Tryptophan (Trp). The prepared electrode (PTh/GPE) showed a good improvment in catalytic activity of electrochemical oxidation DA, UA and Trp, leading to significant improves in the supposed peak currents and decreasing the peak potentials. In the calibration curve obtained from Linear sweep voltammetry it was illustrated the peak currents of DA, UA and Trp enhanced linearly with their concentration. The concentration range was found for DA, UA and Trp, 10-180 μmol L −1 , 6-180 µmolL -1 and 6-180 μmol L −1 in 0.1 M phosphate buffer solution (pH 4.0) respectively. The anodic peak height of analytes was investigated in different pH and scan rates and the optimum pH and scan rate was obtained. The LODs (S/N= 3) were 1, 0.57 and 0.61 µM for DA, UA and Trp, respectively. Consequently, the applicability of the voltammetric sensor was evaluated by simultaneous determination of DA, UA and Trp in biological samples. This present sensor showed valuable characteristics such as stability and repeatability during analytical experiments.

Atmospheric aerosol particles are abundant and ubiquitous in both indoor and outdoor environments. Organic acid species in aerosols have an understudied effect on the environment and human well-being due to their unique interfacial properties. While it is widely accepted that the chemical and physical evolution of aerosol particles in the atmosphere is closely connected to interface-related phenomena, interface-specific methods suitable for investigating these topics in situ have only recently become available. In this study, we elaborate on the recent development of vibrational sum frequency scattering (VSFS) spectroscopy as an interface-specific method for the in situ investigation of the surfaces of submicron aerosol particles suspended in gas. We demonstrate the ability of VSFS to characterize formic and acetic acids, alone and together, at the surfaces of aqueous aerosol particles. We evaluate molecular ordering at the gas/aerosol particle interface by examining polarization-resolved VSFS spectra. Lastly, we quantitatively analyze the interfacial affinity of simple organics for the air/liquid interface, for submicron aerosol surfaces and bulk planar liquid surfaces. These results further support the use of VSFS as an analytical technique for probing the surfaces of small droplets and aerosols and provide insights into differences between the chemistry of planar and highly curved surfaces, with potential significance for atmospheric aerosol chemistry.