Efficient thin-film micro extraction of trace herbicides from food samples using composite electrospun PVC/EVA/CS/Str nanofibers prior to CD-IMS analysis

Abstract

An electrospun composite of poly vinyl chloride/ethylene vinyl acetate/chitosan/starch (PVC/EVA/CS/Str) was synthesized and used as a new sorbent for thin film-micro solid phase extraction (TF-µSPE) of atrazine (ATZ) and ametryn (AMT) prior to corona discharge-ionic mobility spectrometry (CD-IMS) analysis. From the evaluation of scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy, the synthesis of composite nanaofibers was approved. Based on the investigations, thanks to the existence of CS/Str, the synthesized composite nanofibers exhibited large surface area, high porosity, and acceptable reusability. Also, the sorbent provided various interactions with the intended analytes, (hydrophobic contacts, hydrogen bonding, and π-π stacking interactions) resulting in the improvement of extraction efficiency. Effective factors on adsorption and desorption steps were optimized by using both design-expert and one at time method. Under the optimized conditions, the linearity was obtained 8.0-300.0 ng. mL− 1 with determination coefficient (r2) ≥ 0.9821. Limits of detection (LOD) based on S/N = 3 were 2.5 ng.mL− 1 and 2.3 ng. mL− 1 for ATZ and AMT, respectively. The relative standard deviations (RSDs) were in range of between 4.8 and 7.0%. Finally, the efficiency of the TF-µSPE-CD-IMS method was evaluated for the determination of ATZ and AMT in lettuce, tomato, and milk samples with good recoveries (88.6 to 98.1%).