Modern farming relies highly on pesticides to protect agricultural food items from insects for high yield and better quality. Increasing use of pesticide has raised concern about its harmful effects on human health and hence it has become very important to detect even small amount of pesticide residues. Raman spectroscopy is a suitable nondestructive method for pesticide detection, however, it is not very effective for low concentration of pesticide molecules. Here, we report an approach based on plasmonic enhancement, namely, particle enhanced Raman spectroscopy (PERS), which is rapid, nondestructive and sensitive. In this technique, Raman signals are enhanced via the resonance excitation of localized plasmons in metallic nanoparticles. Gold nanostructures are promising materials that have ability to tune surface plasmon resonance frequency in visible to near-IR, which depends on shape and size of nanostructures. We synthesized gold nanorods (GNRs) with desired shape and size by seed mediated growth method, and successfully detected very tiny amount of pesticide present on food items. We also conformed that the detection of pesticide was not possible by usual Raman spectroscopy.

Date Published: 28 August 2014
PDF: 4 pages
Proc. SPIE 9169, Nanoimaging and Nanospectroscopy II, 916908 (28 August 2014); doi: 10.1117/12.2060775

Published in SPIE Proceedings Vol. 9169:
Nanoimaging and Nanospectroscopy II
Prabhat Verma; Alexander Egner, Editor(s)