title: Halloysite nanotubes-titanium dioxide as a solid-phase microextraction coating combined with negative corona discharge-ion mobility spectrometry for the determination of parathion.
abstract: Halloysite nanotubes-titanium dioxide (HNTs-TiO2) as a biocompatible environmentally friendly solid-phase microextraction (SPME) fiber coating was prepared. HNTs-TiO2 was chemically coated on the surface of a fused-silica fiber using a sol-gel process. Parathion as an organophosphorus pesticide was selected as a model compound to investigate the extraction efficiency of the fiber. The extracted analyte was detected by negative corona discharge-ion mobility spectrometer (NCD-IMS). The effective parameters on the extraction efficiency, such as salt effect, extraction temperature and extraction time were investigated and optimized. The extraction efficiency of HNTs-TiO2 fiber was compared with bare-silica (sol-gel based coating without HNTs-TiO2), HNTs, carbon nanotubes and commercial SPME fibers (PA, PDMS, and PDMS-DVB). The HNTs-TiO2 fiber showed highest extraction efficiency among the studied fibers. The intra- and inter-day relative standard deviations were found to be 4.3 and 6.3%, respectively. The limit of detection and limit of quantification values were 0.03 and 0.1 μg L(-1), respectively. The dynamic range of the method was in the range of 0.1-25 μg L(-1). The spiking recoveries were between 85 (±9) and 97 (±6). The SPME-HNTs-TiO2 combined with NCD-IMS was successfully applied for the determination of parathion in apple, strawberry, celery and water samples.
authors.affiliation: Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran. Electronic address: saraji@cc.iut.ac.ir.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Saraji
authors.affiliation: Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran.
authors.forename: Mohammad Taghi
authors.initials: MT
authors.lastname: Jafari
authors.affiliation: Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Mossaddegh
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D000077215:Clay; D007306:Insecticides / Q000032:analysis*; D057230:Limit of Detection; D008855:Microscopy, Electron, Scanning; D043942:Nanotubes / Q000737:chemistry*; D010278:Parathion / Q000032:analysis*; D052617:Solid Phase Microextraction / Q000379:methods*; D014025:Titanium / Q000737:chemistry*
chemical_list: D000538:Aluminum Silicates; D007306:Insecticides; C009495:titanium dioxide; D010278:Parathion; D014025:Titanium; D000077215:Clay
keywords: Fruit and vegetable samples; Halloysite nanotubes-titanium dioxide; Negative corona discharge-ion mobility spectrometry; Parathion; Solid-phase microextraction; Water