Nondestructive Detection of Pesticide Residue Concentration in Apple by Raman Spectral Technology

Abstract. Apple is the world largest produced and consumed fruit item. Apple also ranks number one for pesticide contamination among the fruits. With growing production and consumption of apple, it has become important to concerned stakeholders to detect minimum trace value of pesticide residue present in apple surface in real time basis. A self developed hardware and software equipped with Raman Spectroscopy was used to detect the pesticide content in apple surface. Apple samples of different size and shape were bought from local market. The apples were cleaned and ringed properly to ensure the surface free of pesticide. Organophosphorous pesticide namely Chlorpyrifos and Trichlorfon were mixed with appropriate solvent to prepare pesticide solution of different concentrations. Known concentration of pesticide solution was put into ringed samples’ surface and left to dry for 2 hours. Raman spectral data from different points of apple sample were collected using optical instrument setup in the laboratory. Based on height of the peaks representing the definite group of pesticide, a prediction model was developed which was used in the self developed program to detect the concentration of pesticide residue in apple surface. The laboratory based prototype developed in this research could detect the pesticide residue at each point of apple surface within 3 seconds. The result of the research is promising and can be a milestone for development of industrially feasible technology for rapid, non-destructive and real time detection of different types of pesticide with its concentration in apple surface.