Recent Progress in Non-Enzymatic Electroanalytical Detection of Pesticides Based on the Use of Functional Nanomaterials as Electrode Modifiers

This review presents recent advances in the non-enzymatic electrochemical detection and quantification of pesticides, focusing on the use of nanomaterial-based electrode modifiers and their corresponding analytical response. The use of bare glassy carbon electrodes, carbon paste electrodes, screen-printed electrodes, and other electrodes in this research area is presented. The sensors were modified with single nanomaterials, a binary composite, or triple and multiple nanocomposites applied to the electrodes’ surfaces using various application techniques. Regardless of the type of electrode used and the class of pesticides analysed, carbon-based nanomaterials, metal, and metal oxide nanoparticles are investigated mainly for electrochemical analysis because they have a high surface-to-volume ratio and, thus, a large effective area, high conductivity, and (electro)-chemical stability. This work demonstrates the progress made in recent years in the non-enzymatic electrochemical analysis of pesticides. The need for simultaneous detection of multiple pesticides with high sensitivity, low limit of detection, high precision, and high accuracy remains a challenge in analytical chemistry

Effects of strontium doping on microstructure and functional properties of solution-derived potassium sodium niobate thin films

The effects of strontium doping (0-2 mol%) on structure, microstructure and functional properties of potassium sodium niobate (KNN) thin films deposited on Pt(111)/TiOy/SiO2/Si substrates were investigated. Incorporation of Sr up to 1 mol% into the KNN crystal lattice hindered the grain growth, vertical roughness and contributed to the fine-grained and dense thin film microstructure with monoclinic crystal syngony. This effectively reduced leakage current and improved ferroelectric characteristics. Higher doping content (2 mol%) led to the formation of secondary phases and complete deterioration of functional properties. Stabilization of 1 mol% Sr-doped KNN solution with diethanolamine resulted in the film with dielectric constant and losses of 394 and 0.018 at 100 kHz, respectively, leakage current of 3.8 . 10(-8) A/cm(2) at 100 kV/cm and well saturated ferroelectric hysteresis with P-r of 6.8 mu C/cm(2) and low E-c of 85 kV/cm. Benefiting from improved leakage current characteristics at high electric fields and less defect structure, the film showed maximal local piezoelectric coefficient, d(33) similar to 110 pm/V determined by piezo-response force microscopy (PFM), ability to reach fully saturated local hysteresis under low switching DC voltage of 15 V and good ferroelectric domain mobility proven by successful in-situ poling of chosen area using PFM lithography