Multivariate data analysis of pesticide residue on spinach leaves based on ft-ir spectroscopy

Abstract

Vegetables are susceptible to diseases and pest attack; hence pesticides are widely used by farmers to avoid or reduce pests. The use of pesticides may leave some residues on the vegetables after harvesting and not safe for consumption. Thus, it is essential to monitor the levels and concentrations of pesticide residues in vegetables. Currently, gas chromatography and high-performance liquid chromatography are used as a method for detecting the components of pesticide residues in vegetables. However, these methods are destructive and often time consuming. Therefore, in this study, Fourier transform infrared (FT-IR) spectroscopy combined with multivariate data analysis was selected as a rapid, non-destructive method to obtain spectral information from pesticide residues. Spinach leaves were sprayed with malathion followed by washing treatments. The results showed that washed and non-washed samples can be clearly distinguished, with non-washed samples showing a high absorbance intensity at 970 cm-1 which belongs to the ester functional group that can be used to determine malathion. This approach can be further developed as a routine analysis tool for quantification of the safe range of pesticide residue concentrations in vegetables.