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Indexed by:期刊论文

Date of Publication:2017-02-01

Journal:SENSORS AND ACTUATORS B-CHEMICAL

Included Journals:SCIE、EI

Volume:238

Page Number:427-433

ISSN No.:0925-4005

Key Words:Dissolution of gold nanoparticles; Colorimetric analysis; Organophosphrous pesticide; Point-of-care; Paper device

Abstract:A simple and sensitive colorimetric method is developed for organophosphrous pesticides (OPs) analysis based on the enzymatic hydrolysis reaction of acetylcholinesterase and the dissolution of gold nanoparticles (AuNPs) in Au3+-cetyltrimethylammonium bromide (Au3+-CTAB) solution. In the absence of OPs, the enzymatic hydrolysis product, thiocholine, would reduce Au3+ and protect the AuNPs from dissolution by the Au3+-CTAB. In the presence of OPs, however, the activity of AChE is inhibited, which could not or could only produce a small amount of thiocholine to consume the Au3+. In this case, the large amount of residual Au3+ dissolves the AuNPs and decreases both the concentration and size of the AuNPs, thus leading to an obvious red-to-light pink or red-to-colorless color change. Under optimal conditions, the colorimetric method could indicate the presence of OPs, with the concentration down to 0.7 ppb. After loading AuNPs on a cellulose paper, an AuNPs-coated dipstick is developed for the detection of OPs, which is highly sensitive with an observable limit of detection of 35 ppb. Practical sample analyses in tap water, apple washing solution, and sea water indicate the colorimetric method has acceptable accuracy and good stability, even in the system containing 5 M of NaCl. Regarding these merits, the as-proposed method could be applied for the point-of-care analysis of OPs in complex systems. (C) 2016 Elsevier B.V. All rights reserved.