Nylon 6,6 modified screen printed carbon electrodes as electrochemical sensors for rapid chlorothalonil determination in water samples using differential pulse cathodic stripping voltammetry

A newly developed electrochemical sensor for chlorothalonil based on nylon 6,6 film deposited onto screen printed electrode (SPE) with electrochemical modulation of pH at the electrode/solution interface was studied for the first time. Differential pulse cathodic stripping voltammetry (DPCSV) was used to carry out the electrochemical and analytical studies. Experimental parameters such as accumulation potential, initial potential, accumulation time and pH of Britton-Robinson buffer have been optimized. Chlorothalonil gave optimum analytical signal in a medium of 0.04 M Britton-Robinson buffer at pH 6.0. A well-defined reduction peak was observed, at Ep= −0.851 and −0.938 V vs. Ag/AgCl (3.0 M KCl) for both bare SPE and modified SPE, respectively. The peak currents of modified SPE were significantly increased as compared to bare SPE. At the modified SPE, a linear relationship between the peak current and chlorothalonil concentration was obtained in the range from 0.1 to 2.8 × 10−6 M with a detection limit of 1.53 × 10−8 M (S/N= 3). The practical applicability of the newly developed method has been demonstrated on analyses of real water samples. The newly developed sensor shows good reproducibility with RSD of 3.92%. The nylon 6,6 modified SPE showed itself as promising sensor with good selectivity for chlorothalonil determination

Green sensors for voltammetric determination of lindane in water samples using bare and nylon 6,6 modified pencil electrodes

Lindane, an insecticide, was determined using the differential pulse cathodic stripping voltammetry technique on bare and nylon 6,6 modified pencil electrodes. Experimental parameters, such as pH, accumulation time, accumulation potential and initial potential, were optimized. A well-defined peak of lindane was found for both electrodes which was identified at −0.338 V and −0.350 V, respectively. pHs of 8.0 and 7.0 were chosen as the optimum pHs due to a good stripping signal of the reduction peak for both bare and nylon 6,6 modified pencil electrodes. There were no significant interfering ion effects on the electroanalysis of lindane. The limits of determination for bare and nylon 6,6 modified pencil electrodes were 2.13 × 10−8 M and 3.81 × 10−8 M. The nylon 6,6 modified pencil electrode exhibited a significant increase in the stripping response toward lindane determination as compared to the bare pencil electrode. Water samples were prepared by spiking known concentrations of lindane and the recovery value achieved at both bare and nylon 6,6 modified pencil electrodes was ≥95.3% with RSDs ≤ 3.22%. Ultimately, the proposed methods were relatively selective and highly sensitive and exhibited good precision

Review : physico-chemical modification as a versatile strategy for the biocompatibility enhancement of biomaterials

A biomaterial can be defined as a material intended to interface with biological systems to evaluate, treat, augment or replace any tissue, organ or function of the body. Major problems associated with biomaterials are their properties and biocompatibility, which need to be tackled and resolved before promoting a particular biomaterial to the market or implanting it into a biological system. To enhance the biocompatibility of the biomaterials, several surface modification strategies, such as physico-chemical, mechanical and biological modifications, have been explored. In this review, some recent applications of physico-chemical modification technologies, such as alteration in the structure of a molecule by chemical modification, surface grafting, abrasive blasting and acid etching, surface coatings, heat and steam treatment for medical materials such as polymers, metals, ceramics and nanocomposites are discussed. This article will promote physico-chemical modification as a versatile technology in surface engineering to improve the properties and biocompatibility of medical materials. Furthermore, it will instigate the growth of the biomaterial market with various high quality biomaterials