Determination of dimethoate and phosmet pesticides with surface-enhanced Raman spectroscopy

ABSTRACT

Surface-enhanced Raman spectroscopy spectra of dimethoate and phosmet pesticides were recorded using a Klarite substrate. Significant enhancements were achieved with dimethoate over a concentration range of 0.5–10 µg mL⁻¹ and phosmet over a concentration range of 0.1–10 µg mL⁻¹. The best prediction model for dimethoate pesticide was achieved with a correlation coefficient of 0.940 and a root mean square error of prediction of 0.864 µg mL⁻¹, with the first derivative and standard normalized variate data preprocessing, and the best prediction model of phosmet pesticide was achieved with a correlation coefficient of 0.949 and a root mean square error of prediction of 0.741 µg mL⁻¹ with the first derivative data preprocessing. Our study shows that pesticides, including dimethoate and phosmet, could be quantitatively measured at as low as 0.5 µg mL⁻¹ level using surface-enhanced Raman technology coupled with a Klarite substrate and the results indicated that surface-enhanced Raman spectroscopy with a Klarite substrate has potential for the analysis of dimethoate and phosmet residues.

KEYWORDS:

• Data preprocessing
• dimethoate and phosmet pesticides
• partial least squares regression
• surface-enhanced Raman spectroscopy