EFFECT OF CITRATE CAPPED GOLD NANOPARTICLES VOLUME ON ACEPHATE DETECTION USING COLORIMETRIC ASSISTED IMAGE PROCESSING TECHNIQUE

Abstract

Acephate (Ac) is an organophosphate (OPP) that is widely used as an insecticide. It is highly toxic, thus simple, and rapid detection method of Ac is in urgent demand. Citrate capped gold nanoparticles (Cit-AuNPs) are excellent materials for colorimetric detection of OPPs. The effect of Cit-AuNPs and Ac volume ratio (Cit-AuNPs: Ac) on the colorimetric sensor capability was evaluated for detection of Ac in this study. Cit-AuNPs were synthesised via reduction of chloroauric acid (HAuCl4) using tri-sodium citrate dihydrate and used to detect Ac. Colour images of all complexes formed were captured and digitised using ImageJ software to obtain red values (RVs) as the response of the detection. Analysis using Ultraviolet-Visible (UV-Vis) spectrophotometer and High Resolution-Transition Electron Microscope (HRTEM) were employed to examine the red shift and Cit-AuNPs aggregation, respectively,
whereas Fourier Transform Infra-red (FTIR) was used to investigate chemical interaction between Cit- AuNPs and Ac after the detection. The results of this study demonstrated that the lowest volume ratio of Cit-AuNPs: Ac (1:9) was sufficient to produce obvious colour change for the detection of Ac.
Keywords: Acephate; colorimetric detection; gold nanoparticles; organophosphate; image processing.

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