Analytical Sciences

Abstract − Analytical Sciences, 35(6), 631 (2019).

Silver Nanoparticles with Sodium Dodecyl Sulfate as a Colorimetric Probe for the Detection of Dithiocarbamate Pesticides in Environmental Samples
Saima Ameen GHOTO, Muhammad Yar KHUHAWAR, and Taj Muhammad JAHANGIR
Institute of Advanced Research Studies and Chemical Sciences, University of Sindh, Jamshoro 76080, Pakistan
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.