Non-linear responses via agglomeration and aggregation of gold nanoparticles for surface-enhanced Raman spectroscopy (SERS) coupled with chemometric analysis for chlorpyrifos detection

Xiaotong Liu, Udit Pant, Natasha Logan, Qiqi He, Brett Greer, Christopher T. Elliott, Cuong Cao*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

This study investigates the behaviour of gold nanoparticles (AuNPs) when exposed to chlorpyrifos, an agricultural pesticide, and its application in detecting the pesticide via surface-enhanced Raman spectroscopy (SERS). Under synergistic addition of NaCl, AuNPs undergo agglomeration at lower chlorpyrifos concentrations but aggregation at higher concentrations, resulting in a distinctive nonlinear SERS response. A linear relationship is obtained between 0.001 and 1 ppm with detection limit (LOD) of 0.009 ppm, while an inverse response is observed at higher concentrations (1–1000 ppm) with a LOD of 1 ppm. Combining the colorimetric response of AuNP solutions, their absorbance spectra, and principal component analysis can improve detection reliability. The assay, coupled with a simple recovery method using acetonitrile swabbing, achieves high reproducibility in detecting chlorpyrifos in cucumber, even at concentrations as low as 0.11 ppm. This approach can be tailored for various chlorpyrifos concentrations not only in cucumbers but also in different food matrices.
Original languageEnglish
Article number 139944
JournalFood Chemistry
Early online date03 Jun 2024
DOIs
Publication statusEarly online date - 03 Jun 2024

Keywords

  • SERS
  • Chlorpyrifos
  • Gold nanoparticle
  • Agglomeration
  • Aggregation
  • Chemometric analysis

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