Sol–gel/nanoclay composite as a solid-phase microextraction fiber coating for the determination of organophosphorus pesticides in water samples

Abstract

A novel solid-phase microextraction (SPME) fiber coated with a sol-gel/nanoclay composite was prepared by the sol-gel technique involving the hydrolysis reaction of alkoxysilanes and the subsequent condensation reaction with hydroxyl groups of the nanoclay on a stainless steel wire. A method based on direct immersion SPME and gas chromatography-corona discharge ion mobility spectrometry was developed for the determination of four organophosphorus pesticides in aqueous samples. The effect of different experimental parameters on the extraction efficiency of the method was investigated. The sol-gel/nanoclay fiber showed higher extraction performance for the organophosphorus pesticides compared with Ppy/nanoclay, sol-gel coating, and three commercial fibers (polydimethylsiloxane (PDMS), PDMS/divinylbenzene (DVB), and polyacrylate (PA)). Limits of detection (LOD) and quantitation (LOQ) of the method were in the range of 0.003-0.012 and 0.01-0.02 μg L(-1), respectively. The calibration curves were linear in a concentration range from 0.01 to 2.0 μg L(-1) (r (2) > 0.995). The relative standard deviations for intra- and inter-day precision were 3.3-5.6 and 6.4-8.4 %, respectively. Fiber-to-fiber reproducibility for three prepared fibers was 7.4-10.2 %. Finally, the method was successfully applied for the extraction of the studied compounds from water samples. The relative recovery obtained for the spiked real-water samples were 86-104 %.

Sol–gel/nanoclay composite as a sorbent for microextraction in packed syringe combined with corona discharge ionization ion mobility spectrometry for the determination of diazinon in water samples

“…This sorbent was used for further experiments. It is worth mentioning that the sol–gel/nanoclay composite # 1 which had a similar composition to the previously reported SPME coating showed lower extraction efficiency than the present sorbent. It seemed that phenyl groups of PTMOS promoted efficiency of the present sorbent due to π–π interaction with the analyte.…”

“…Furthermore, this modification expands the interlayer spacing in nanoclay and makes the material more hydrophobic . So far, the composite of montmorillonite with organic polymers (e.g., polyaniline, polypyrrole, and polythiophene) and silica have been applied as sorbents for analytical purposes .…”

“…In our previous work, a sol–gel/nanoclay composite using two alkoxysilanes (TEOS and MTMOS) was prepared and used as SPME fiber . Compared to commercial SPME fibers (PDMS, PDMS/DVB, and PA), the fiber showed higher efficiency for the extraction of organophosphorus pesticides.…”

Emerging materials for sample preparation

“…Besides MMT, other nanoclays as cloisite have been incorporated in SPME devices . This nanoclay was incorporated in an SPME device following a sol–gel process involving the hydrolysis reaction of alkoxysilanes and the subsequent condensation reaction with hydroxyl groups of the nanoclay on a stainless‐steel wire.…”

Extraction of organophosphorus pesticides by carbon‐coated Fe3O4 nanoparticles through response surface experimental design

“…Several methodologies have been reported for determining OPP residues in aqueous samples preceded by different preconcentration procedures, including SPE , SPME , hollow fiber membrane (HFM) combined with protected LPME , dispersive liquid–liquid microextraction (DLLME) and other techniques based on DLLME principles, such as homogeneous liquid–liquid microextraction (HLLME) . In recent years, magnetic solid‐phase extraction (MSPE), as a current and efficient method, has attracted much research interest .…”