Nanofibrous Online Solid-Phase Extraction Coupled with Liquid Chromatography for the Determination of Neonicotinoid Pesticides in River Waters

Abstract

Polymeric nano- and microfibers were tested as potential sorbents for the extraction of five neonicotinoids from natural waters. Nanofibrous mats were prepared from polycaprolactone, polyvinylidene fluoride, polystyrene, polyamide 6, polyacrylonitrile, and polyimide, as well as microfibers of polyethylene, a polycaprolactone nano- and microfiber conjugate, and polycaprolactone microfibers combined with polyvinylidene fluoride nanofibers. Polyimide nanofibers were selected as the most suitable sorbent for these analytes and the matrix. A Lab-In-Syringe system enabled automated preconcentration via online SPE of large sample volumes at low pressure with analyte separation by HPLC. Several mat layers were housed in a solvent filter holder integrated into the injection loop of an HPLC system. After loading 2 mL sample on the sorbent, the mobile phase eluted the retained analytes onto the chromatographic column. Extraction efficiencies of 68.8–83.4% were achieved. Large preconcentration factors ranging from 70 to 82 allowed reaching LOD and LOQ values of 0.4 to 1.7 and 1.2 to 5.5 µg·L−1, respectively. Analyte recoveries from spiked river waters ranged from 53.8% to 113.3% at the 5 µg·L−1 level and from 62.8% to 119.8% at the 20 µg·L−1 level. The developed methodology proved suitable for the determination of thiamethoxam, clothianidin, imidacloprid, and thiacloprid, whereas matrix peak overlapping inhibited quantification of acetamiprid.

The utilization of open‐source microcontroller boards and single‐board computers in liquid chromatography

“…The Trinket M0 device is similar to an Arduino, but has a much smaller form factor, making it ideal for space‐limited applications such as this integrated lab‐in‐syringe. Initially, the Trinket device was used to control a single solenoid valve so that an isocratic LC pump could switch between mobile phase reservoirs and provide gradient elution functionality during the post‐extraction analysis of sulfonamide antibiotics in urine samples [34] and neonicotinoid pesticides in water samples [35]. Use of this microcontroller board was later expanded to include control of a magnetic stirrer motor used in the syringe manifold and for triggering instrument injection, pumps, and data acquisition for the LC‐FLD analysis of fluoroquinolones in water samples [36] and the LC‐MS/MS analysis of beta‐blockers in serum [37].…”