Single-walled carbon nanotube/silica composite as a novel coating for solid-phase microextraction fiber based on sol-gel technology

Abstract

Single walled carbon nanotubes (SWCNTs)/silica composite coating for solid phase microextrac tion synthesized by sol−gel technology was developed for air sampling and determination of perchloroethylene, benzotrichloride, chloromethyl methyl ether and trichloroethylene. Application of this method was investigated under different laboratory conditions. Predetermined concentrations of each analyte were prepared in a home made standard chamber and the influence of temperature, humidity, extraction time, storage time, desorption temperature and desorption time was investigated. Under optimal conditions, the use of SWCNTs/silica com posite fiber showed high sensitivity and fast sampling of halogenated volatile organic compounds from air. For linearity test, the regression correlation coefficient was more than 98% for analytes of interest and linear dynamic range for the proposed fiber and the applied gas chromatography−flame ionization detector (GC−FID) technique was from 1 to 100 ng/mL Method detection limits ranged from 0.11 to 0.2 ng/mL and method quan tification limits were between 0.34 and 0.7 ng/mL. SWCNTs/silica composite fiber was highly reproducible; rel ative standard deviations were between 5.6 and 11.7%. The developed method was applied to determine per chloroethylene concentration of real air samples of a dry cleaning shop and the results compared with the data obtained with commercially available carboxen/polydimethylsiloxane (CAR/PDMS).

Occupational Exposure and Risk Assessment of Formaldehyde in the Pathology Departments of Hospitals

“…Formaldehyde also is an important precursor to many other materials and chemical compounds. Because of these properties, exposure to formaldehyde has adverse effects (Jalili et al, 2019;Barkhordari et al, 2017;Attari et al, 2015) on health, including acute effects (e.g., bronchial asthma (Suzuki et al, 2017), chemosensory irritation (Bellisario et al, 2016;Persoons et al, 2011;Vimercati ppm. The recommended exposure limit (REL) of the National Institute for Occupational Safety and Health (NIOSH) for formaldehyde is 0.016 ppm (8-hour TWL) (Vohra, 2011).…”

Numerical Characterization for Electrical Conductivity of Two-Dimensional Nanocomposite Systems with Conducting Fiber Fillers

“…For additional improvement of the performance, the incorporation of particulate fillers can be considered to form the excluded volume that effectively leads to a segregated CNT network [14][15][16][17][18]. In consequence, the probability of CNTs forming a conducting network increases in the segregated composite system, indicating that much lower CNT loading suffices to reach a certain degree of the electrical conductivity [15].…”

Development of Cold Fiber Head Space Solid-Phase Microextraction for Analysis of 2,5 Hexandion in Urine

“…Over the last decade, several methods based on solid phase microextraction are reported in the analysis of pollutants in air and extraction of analytes from urine samples [10][11][12][13][14][15][16][17]. The most developed methods to determine volatile biological indexes in urine samples are static or dynamic headspace and head space-solid phase microextraction (HS-SPME).…”