Ghoto Saima Ameen, Khuhawar Muhammad Yar, Jahangir Taj Muhammad
Institute of Advanced Research Studies and Chemical Sciences, University of Sindh.
Anal Sci. 2019 Jun 10;35(6):631-637. doi: 10.2116/analsci.18P417. Epub 2019 Feb 8.
A rapid and simple colorimetric approach has been developed for sensing dithiocarbamate pesticides (ziram, zineb and maneb) in environmental samples using sodium dodecyl sulfate capped silver nanoparticles (SDS-AgNPs). They were characterized by a UV-vis spectrophotometer, FT-IR, SEM and EDX. Dithiocarbamates on interactions with SDS-AgNPs induce the aggregation of NPs, leading to a color change from yellow to greyish or dark brownish, depending on the concentration of pesticides added. A shift in the wavelength was observed from 400 to 570 nm with the broad band. The absorption ratio, 570/400 nm, was found to be linearly related to the concentration of pesticides in the range of 195.7 - 733.9 ng/mL for ziram, 17.6 - 66.2 ng/mL for zineb and 16.9 - 63.6 ng/mL for maneb with the detection limits of 149.3, 4.0 and 9.1 ng/mL for ziram, zineb and maneb, respectively. The method was successfully applied for the determination of DTCs in environmental samples (tap water, tomato, mango beverage) with percentage recoveries of 94.8 - 108.4% for ziram, 93.7 - 105.4% for zineb and 93.2 - 107.6% for maneb. The procedure was repeatable with inter-day RSD (n = 5) within 3.4, 4.8, 7.6% and intra-day RSD (n = 5) within 1.2, 1.7 and 1.8% for the ziram, zineb and maneb respectively.
已开发出一种快速简便的比色法，用于使用十二烷基硫酸钠包覆的银纳米颗粒（SDS-AgNPs）检测环境样品中的二硫代氨基甲酸盐类农药（福美锌、代森锌和代森锰锌）。通过紫外可见分光光度计、傅里叶变换红外光谱仪、扫描电子显微镜和能谱仪对其进行了表征。二硫代氨基甲酸盐与SDS-AgNPs相互作用会诱导纳米颗粒聚集，导致颜色从黄色变为灰色或深棕色，这取决于添加的农药浓度。观察到宽带波长从400 nm移至570 nm。发现吸收比570/400 nm与农药浓度呈线性关系，福美锌的浓度范围为195.7 - 733.9 ng/mL，代森锌为17.6 - 66.2 ng/mL，代森锰锌为16.9 - 63.6 ng/mL，福美锌、代森锌和代森锰锌的检测限分别为149.3、4.0和9.1 ng/mL。该方法成功应用于环境样品（自来水、番茄、芒果饮料）中二硫代氨基甲酸盐的测定，福美锌的回收率为94.8 - 108.4%，代森锌为93.7 - 105.4%，代森锰锌为93.2 - 107.6%。该方法具有可重复性，福美锌、代森锌和代森锰锌的日间相对标准偏差（n = 5）分别在3.4%、4.8%、7.6%以内，日内相对标准偏差（n = 5）分别在1.2%、1.7%和1.8%以内。
