Loading...

Label-Free Colorimetric Detection of Methiocarb Insecticid Based on Aggregation of Gold Nanoparticles

Mohammadi Avizi, Ali Akbar | 2017

741 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 49973 (03)
  4. University: Sharif University of Technology
  5. Department: Chemistry
  6. Advisor(s): Hormozi-Nezhad, Mohammad Reza
  7. Abstract:
  8. Methiocarb [3,5-dimethyl-4-(methylthio) phenyl methylcarbamate] is an N-methylcarbamate with neurotoxic action. Because carbamate pesticides are acetylcholinesterase inhibitors, they are considered to be carcinogens and mutagens. Methiocarb pesticide is widely used throughout the world particularly effective as fungicides, insecticide and bird repellent. To prevent its harmful effects on animals, humans, and the environment, it is of crucial importance to develop simple and sensitive methods for in-situ detection of methiocarb. This research describes a simple and low-cost method for on-site monitoring of methiocarb insecticide. Gold nanoparticles (AuNPs) aggregation caused by methiocarb, served as colorimetric response. We demonstrated detection capability of methiocarb both in solution- and substrate-based sensor.In the first part of this research, it was investigated the response of citrate-capped AuNPs toward methiocarb by a UV-vis spectrometer. The effective parameters on aggregation process including ionic strength, concentration of AuNPs, pH and time were considered to find the optimum analytical condition for the detection of methiocarb. A good linear relationship was obtained between the colorimetric response and the concentration of methiocarb ranging from 20.0 to 80.0 ng mL-1 with a limit of detection of 5.0 ng mL-1.In the second part of this research, hydrophilic filter paper soaked in agarose solution was bounded by hydrophobic solid wax and then was coated with unmodified AuNPs. The addition of methiocarb drop caused a change of its color from red to purple or blue. The effect of critical parameters on the test strip response (i.e. the ratio of blue to red intensity of image) including percent of agarose gel and AuNPs volume were optimized. The colorimetric response of optimized sensor showed a good linear relationship ranging from 1.0 to 20.0 µg mL-1 and a limit of detection of 0.5 µg mL-1
  9. Keywords:
  10. Gold Nanoparticle ; Colorimetric ; Aggregation Method ; Pesticide ; Methiocarb Pesticide ; Paper Strip

 Digital Object List

 Bookmark

No TOC