Surface modification of silver nanoparticles with dopamine dithiocarbamate for selective colorimetric sensing of mancozeb in environmental samples

We report the use of dopamine dithiocarbamate functionalized silver nanoparticles (DDTC-Ag NPs) as a colorimetric probe for sensing of mancozeb in environmental water and fruit juice samples. The DDTC-Ag NPs were characterized by UV-visible spectrometry, FT-IR, H-1 NMR, dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. It is observed that the mancozeb induces the aggregation of DDTC-Ag NPs via Michael addition and enamine formation between DDTC-Ag NPs and mancozeb, leading to a color change from brownish orange to bluish, which can be seen with naked eyes, and measured by UV-visible spectrometry, TEM and DLS. The response is linearly dependent on the concentration of mancozeb in the range from 5 x 10(-5) to 3 x 10(-4) M, and the limit of detection is 21.1 x 10(-6) M. The present method is very close to the gas chromatography (GC) for the analysis of mancozeb in apple juice sample. The proposed method provided a very fast and efficient procedure to detect mancozeb from various environmental water (tap, canal and river) and fruit juice (apple, grape, and tomato) samples with minimized sample preparations. (C) 2014 Elsevier B.V. All rights reserved.