Analysis of Pesticide Residue in Tomatoes by Carbon Nanotubes/β‐Cyclodextrin Nanocomposite Reinforced Hollow Fiber Coupled with HPLC

For addressing the issues of pesticide residue analysis characterized by the trace levels of target analytes and the complexity of sample matrices, a selective extracting material, carbon nanotubes (CNTs)/β-cyclodextrin (β-CD) nanocomposite reinforced hollow fiber (HF), was developed. CNTs were chemically modified with β-CD and then the resultant nanocomposite was immobilized into the wall pores and lumen of HF by sol-gel technology. The reinforced HF was applied to direct-immersion mode of solid phase microextraction for the determination of carbaryl and 1-naphthol in tomatoes, coupled with high performance liquid chromatography. The proposed method provided 240- and 215-fold enrichment factors, good linearity in the range of 0.6 to 600 ng/g and 0.2 to 600 ng/g, good repeatability with RSDs of 4.5% and 6.9%, and batch-to-batch reproducibility with RSDs of 7.4% and 8.3% for 1-naphthol and carbaryl, respectively. Moreover, the low limits of detection at 0.05 and 0.15 ng/g for 1-naphthol and carbaryl, respectively, along with the high recovery in the range of 84.2% to 108.9% were obtained. The results showed that the material combined the respective advantages of CNTs, β-CD, and HF, thus, exhibiting efficient adsorption property, outstanding molecular recognition performance, and excellent sample clean-up effect, and it is applicable for pesticide residue analysis in complex matrices. PRACTICAL APPLICATION: The developed extracting material can be used for pesticide residue analysis of tomatoes. Pesticides, carbaryl, and 1-naphthol were detected in tomatoes, the most popular vegetable grown and consumed globally. The results supported the necessity to monitor pesticide residue for public health.