National Laboratory for Nanotechnology in Agribusiness (LNNA), Embrapa Instrumentation, 13560-970 São Carlos, SP, Brazil; Center for Exact Sciences and Technology, Federal University of São Carlos (UFSCar), 13565-905 São Carlos, SP, Brazil.
National Laboratory for Nanotechnology in Agribusiness (LNNA), Embrapa Instrumentation, 13560-970 São Carlos, SP, Brazil.
Talanta. 2017 May 15;167:59-66. doi: 10.1016/j.talanta.2017.02.005. Epub 2017 Feb 3.
Organophosphate (OP) compounds impose significant strains on public health, environmental/food safety and homeland security, once they have been widely used as pesticides and insecticides and also display potential to be employed as chemical warfare agents by terrorists. In this context, the development of sensitive and reliable chemical sensors that would allow in-situ measurements of such contaminants is highly pursued. Here we report on a free-enzyme impedimetric electronic tongue (e-tongue) used in the analysis of organophosphate pesticides comprising four sensing units based on graphene hybrid nanocomposites. The nanocomposites were prepared by reduction of graphene oxide in the presence of conducting polymers (PEDOT:PSS and polypyrrole) and gold nanoparticles (AuNPs), which were deposited by drop casting onto gold interdigitated electrodes. Impedance spectroscopy measurements were collected in triplicate for each sample analyzed, and the electrical resistance data were treated by Principal Component Analysis (PCA), revealing that the system was able to discriminate OPs at nanomolar concentrations. In addition, the electronic tongue system could detect OPs in real samples, where relations between the principal components and the variation of pesticides in a mixture were established, proving to be useful to analyze and monitor mixtures of OP pesticides. The materials employed provided sensing units with high specific surface area and high conductivity, yielding the development of a sensor with suitable stability, good reproducibility, and high sensitivity towards pesticide samples, being able to discriminate concentrations as low as 0.1nmolL. Our results indicate that the e-tongue system can be used as a rapid, simple and low cost alternative in the analyses of OPs pesticide solutions below the concentration range permitted by legislation of some countries.
有机磷 (OP) 化合物作为杀虫剂和农药被广泛使用，同时也有可能被恐怖分子用作化学战剂，对公共卫生、环境/食品安全和国土安全造成重大压力。在这种情况下，开发能够原位测量此类污染物的灵敏可靠的化学传感器受到高度关注。在这里，我们报告了一种基于石墨烯杂化纳米复合材料的自由酶阻抗电子舌（e-tongue）在有机磷农药分析中的应用，该电子舌由四个基于传感单元组成。纳米复合材料是通过在存在导电聚合物（PEDOT:PSS 和聚吡咯）和金纳米粒子 (AuNPs) 的情况下还原氧化石墨烯制备的，通过滴铸将其沉积在金叉指电极上。对每个分析的样品进行了三次阻抗谱测量，并通过主成分分析（PCA）处理电阻数据，结果表明该系统能够在纳摩尔浓度下区分有机磷。此外，电子舌系统能够检测实际样品中的有机磷，建立了主成分与混合物中农药变化之间的关系，证明该系统对于分析和监测有机磷农药混合物非常有用。所使用的材料为传感单元提供了高比表面积和高导电性，从而开发出一种具有适当稳定性、良好重现性和对农药样品高灵敏度的传感器，能够区分低至 0.1nmolL 的浓度。我们的结果表明，该电子舌系统可作为一种快速、简单且低成本的替代方法，用于分析一些国家法规允许浓度以下的有机磷农药溶液。
