Chemistry Department, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia.
Department of Chemistry, Faculty of Science, Ain Shams University, Abbassia, Cairo 11566, Egypt.
J AOAC Int. 2021 Mar 5;104(1):113-121. doi: 10.1093/jaoacint/qsaa098.
The importance of recognizing and quantifying chemical anions/cations found in various types of samples, including environmental and biological samples, has been extensively studied. Recent findings suggest the possibility of health risks caused by organic compound dimethylarsinic acid (DMAs) rather than its inorganic arsenic metabolite.
This article aims to fabricate polymeric-membrane electrochemical sensors with high sensitivity and selectivity for the cacodylic acid sodium salt dimethylarsinate (DMAs) based on silver diethyldithiocarbamate (AgDDTC) and CuIIphthalocyanine (CuPC) as novel neutral carriers and their applications.
DMAs calibration relations and titrations were carried out using a potentiometric workstation equipped with a double-junction reference electrode, in conjunction with the fabricated working electrodes.
Sensors revealed fast and stable anionic response with near-Nernstian slopes (-38.6 ± 0.9 and -31.5 ± 0.6 mV/decade), within concentration ranges (1.7 × 10-5 -1.0 × 10-2 and 3.0 × 10-5 -1.0 × 10-2 M) and detection limits (1.0 × 10-5 and 1.6 × 10-5 M) for AgDDTC- and CuPC-based sensors, respectively. Sensors are characterized by extended life-time, signal stability, high precision and short response times. Selectivity for the cacodylate anion over most common anions was tested for the proposed electrodes. Sensors were satisfactorily applied for DMAs quantification in biological matrices with recoveries ranging between 96.2 and 99.0%. Membrane sensors were interfaced with a flow-through system for continuous monitoring of DMAs. The sensors were tested for the assay of different amino acids based on their reaction with cacodylate, where reaction end points were monitored with the proposed electrodes using direct potentiometric determination and flow injection analysis (FIA).
Potentiometric ion-selective PVC-membrane electrodes based on silver diethyldithiocarbamate (AgDDTC) and CuIIphthalothyanine (CuPC) provide adequate and reliable means for the determination of dimethylarsenate anion (cacodylate anion, DMAs). These membrane electrodes are easy to manufacture, they have the advantages of high selectivity and sensitivity, broad dynamic ranges, low detection limits, quick response times and cost effectiveness. Such properties make these sensors suitable for the assay of DMAs levels in aqueous solutions by direct potentiometry, flow injection and potentiometric titration, as well as in monitoring of the titration end points of the reactions between various amino acids and DMAs anion in aqueous solutions.
Simple electrochemical membranes for dimethylarsinate (DMAs) were prepared, based on diethyldithiocarbamate (AgDDTC) and CuIIphthalocyanine (CuPC). - DMAs sensors were fabricated in two different modules: batch (for static) and flow-through (for hydrodynamic) approaches. - Levels of DMAs were determined in spiked biological samples. - AgDDTC-based sensors were successfully applied in the determination of several amino acids via potentiometric titration with DMAs.
人们已经广泛研究了识别和量化各种类型样品（包括环境和生物样品）中化学阴离子/阳离子的重要性。最近的研究结果表明，有机化合物二甲基砷酸（DMAs）而不是其无机砷代谢物可能对健康构成风险。
本文旨在基于银二乙基二硫代氨基甲酸盐（AgDDTC）和铜酞菁（CuPC）作为新型中性载体，制造用于检测二甲胂酸钠二甲基砷酸盐（DMAs）的聚合物膜电化学传感器，并对其应用进行研究。
使用配备双结参比电极的电位工作站进行 DMAs 校准关系和滴定，同时使用所制备的工作电极。
传感器对带负电荷的离子表现出快速而稳定的响应，AgDDTC 和 CuPC 基传感器的斜率接近 Nernst 斜率（-38.6 ± 0.9 和 -31.5 ± 0.6 mV/decade），浓度范围分别为（1.7 × 10-5 -1.0 × 10-2 和 3.0 × 10-5 -1.0 × 10-2 M）和检测限分别为（1.0 × 10-5 和 1.6 × 10-5 M）。传感器具有较长的使用寿命、信号稳定性、高精度和较短的响应时间。对所提出的电极进行了常见阴离子对二甲胂酸阴离子的选择性测试。传感器可用于生物基质中 DMAs 的定量，回收率在 96.2%至 99.0%之间。将膜传感器与流动系统接口，用于连续监测 DMAs。使用所提出的电极通过直接电位测定和流动注射分析（FIA）对不同氨基酸进行了检测，根据它们与二甲胂酸盐的反应来监测反应终点。
基于银二乙基二硫代氨基甲酸盐（AgDDTC）和铜酞菁（CuPC）的 PVC 聚合物膜离子选择性电极提供了用于测定二甲砷酸盐阴离子（二甲胂酸根，DMAs）的充分可靠方法。这些膜电极易于制造，具有高选择性和灵敏度、宽动态范围、低检测限、快速响应时间和成本效益等优点。这些特性使这些传感器适用于通过直接电位测定、流动注射和电位滴定法直接测定水溶液中 DMAs 的含量，以及监测水溶液中各种氨基酸与 DMAs 阴离子之间反应的滴定终点。
制备了基于二乙二硫代氨基甲酸盐（AgDDTC）和铜酞菁（CuPC）的简单电化学二甲胂酸盐（DMAs）传感器。- 制备了两种不同模块的 DMAs 传感器：批量（用于静态）和流动（用于动态）。- 在加标生物样品中测定 DMAs 水平。- AgDDTC 基传感器成功应用于通过与 DMAs 进行电位滴定来测定几种氨基酸。
