A novel strategy for preparing electrospun thin film microextraction samplers: Determining pesticides in water as proof of concept

Abstract

Thin film microextraction (TFME) greatly benefits from extractive phases with a large surface area, since this feature is paramount for rapid and effective analyte sorption. One of the techniques that can be used for preparation of TFME samplers with large extractive phase surface area is electrospinning. The traditional electrospinning, in which a polymer solution fed through a high-voltage applied nozzle is deposited to the support, may reduce the inter-sampler preparation repeatability and increase the material usage. The present study developed a new single-drop static blade electrospinning technique that can be used for homogenous coating the nano-micro sized fibrous extractive phase on the surface of stainless-steel blade, here shown using electropsun polyacrylonitrile (PAN) embedded with poly(divinylbenzene) (PDVB) nanoparticles as the extractive phase. This technique provided improved control over coating thickness while using less polymer and made it possible to fabricate ultrathin and highly uniform nanofibrous coatings in a reproducible way. The optimized static single droplet electrospinning parameters were applied voltage of 10.4 kV and a tip-to-collector distance of 8.0 cm using a slurry containing PDVB:PAN in a 1:1 ratio.

Three model pesticides (trifluralin, methyl parathion, and diazinon) were used to evaluate the extraction performance of the produced TFME samplers. Gas chromatography-mass spectrometry was then used for analysis. The electrospun PDVB-PAN samplers showed faster adsorption kinetics, with 1.7- and 5.2-fold higher slopes for methyl parathion and trifluralin, respectively, compared to bulk coated PDVB-PAN samplers in the kinetic regime of extraction. Under the same conditions, the bulk coated sampler did not show noticeable peaks for diazinon.

These results show that single-drop static blade electrospinning is a promising technique for creating high-performance TFME samplers. It provides accurate control on sorbent deposition, little material waste, with potential for use in clinical, food, and environmental matrices that require cheap and single use sample preparation devices.