Rapid Quantitative Determination of Multiple Pesticide Residues in Mango Fruits by Surface-Enhanced Raman Spectroscopy
Uyen Thu Pham, Quynh Huong Thi Phan, Linh Phuong Nguyen, Phuong Duc Luu, Tien Duy Doan, Ha Thu Trinh, Cuc T. Dinh, Tai Van Nguyen, Trần Quốc Toàn, Duy Le, Tri Nhut Pham, Dang Truong Le, Duong Thanh Nguyen
Abstract
Imidacloprid, acephate, and carbaryl are common insecticides that are extensively used in planting mango, a well-known fruit in Vietnam, to ease mango hopper issues. The accurate detection of pesticide residues is critical for mango export to meet quality criteria. This study developed a novel SERS platform by using polydimethylsiloxane (PDMS) to simulate the rose petal structure incorporated with a silver coating layer and silver nanoparticles (AgNPs) to detect imidacloprid, acephate, and carbaryl in mango fruits. In this paper, the rose petal PDMS/Ag-AgNPs replica was considered the most efficient substrate for SERS measurement with an EF of 4.7 × 107. The Raman spectra of the three insecticides obtained from the PDMS/Ag-AgNPs substrate were clearly observed with their characteristic peaks of 1105 cm−1 for imidacloprid, 1083 cm−1, and 1579 cm−1 for acephate, and 727 cm−1 and 1378 cm−1 for carbaryl. The application of PDMS/Ag-AgNPs substrate in quantitative analysis of the three pesticides in mango fruit was evaluated. As a result, the limit of detection was 0.02 mg/kg for imidacloprid, 5 × 10−5 mg/kg for acephate, and 5 × 10−3 mg/kg for carbaryl. The SERS result also revealed that the pesticide residues in the mango sample were within an acceptable limit. This suggested the possibility of the rose petal PDMS/Ag-AgNPs replica for rapid quantification of pesticide residues not only in mango fruit but also in many other agricultural products.