Details

Autor(en) / Beteiligte

• Liu, Bicheng
• Wu, Liangming
• Peng, Zoujun
• Wu, Sihao
• Qiu, Ping

Titel

Monitoring of parathion methyl using a colorimetric gold nanoparticle-based acetylcholinesterase assay

Ist Teil von

• Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 2022-03, Vol.268, p.120665, Article 120665

Ort / Verlag

England: Elsevier B.V

Erscheinungsjahr

2022

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• The mechanism for selective detection was based on acetylcholinesterase (AChE) affinities to the special inhibitors of the enzyme by OPs and the hydrolysis product (choline) to interact with Au NPs results in aggregation and color change. [Display omitted] •For the first time, the smartphone-assisted sensor based on oxidase-mimicking activity of AuNPs and enzyme inhibition is successfully demonstrated for monitoring of pesticide in water samples.•The mechanism for selective detection is based on AChE affinities to the special inhibitors of the enzyme by PM and the hydrolysis product (choline) to interact with AuNPs results in aggregation and color change.•The advantages of smartphone-assisted sensors are rapid, selective, cost-effective, and can be applied at the sample source for the determination of PM. A colorimetric gold nanoparticles (AuNPs)-based acetylcholinesterase (AChE) assay was designed for the first time to measure the concentration of parathion-methyl (PM) in lake water samples. In this assay, the analyte PM inhibited the hydrolysis of acetylthiocholine (ATCh) by AChE, preventing the formation of thiocholine (TCh) that would otherwise react with the AuNPs catalyst and deactivate the catalyst. Therefore, in the presence of PM, the AuNPs catalyzed the oxidation of the 3,3′,5,5′-tetramethylbenzidine (TMB) colorimetric indicator to oxTMB, inducing a visual color change from colorless to blue. However, in the absence of PM, AChE hydrolyzed ATCh to TCh, which then reacted with the AuNPs, preventing the oxidation of TMB to oxTMB and rendering the solution colorless. Therefore, the change in the color of the analyte solution indicated the presence of PM, and the absorbance of the resulting solution was measured by UV–Vis spectroscopy to calculate the concentration of PM after generation of a calibration curve. This method was then employed using the smartphone app Color Picker, which converted the color information from the photos of the solution into digital red (R), green (G), and blue (B) values. The ratio of green (G) to blue (B) (G/B) was then plotted against the corresponding concentration to calculate the standard curve, whose regression equation was expressed by y = –0.012x + 1.02 (ng/mL), and the coefficient of determination (R2) was 0.97. In addition, this method was also used to determine the amount of PM in real lake water samples with recovery of 90.2–133.3%.