Search results for "btex"
showing 10 items of 23 documents
Headspace–mass spectrometry determination of benzene, toluene and the mixture of ethylbenzene and xylene isomers in soil samples using chemometrics
2007
A simple and fast method has been developed for the determination of benzene, toluene and the mixture of ethylbenzene and xylene isomers (BTEX) in soils. Samples were introduced in 10 mL standard glass vials of a headspace (HS) autosampler together with 150 microL of 2,6,10,14-tetramethylpentadecane, heated at 90 degrees C for 10 min and introduced in the mass spectrometer by using a transfer line heated at 250 degrees C as interface. The volatile fraction of samples was directly introduced into the source of the mass spectrometer which was scanned from m/z 75 to 110. A partial least squares (PLS) multivariate calibration approach based on a classical 3(3) calibration model was build with m…
The possibilities of using the aspen poplar seeds (Populus tremula L.) for the purpose of removing monoaromatic hydrocarbons from an aqueous solution
2018
Sorption of oil-related products (including mainly the propellants) is the very basic process that counteracts spreading these types of pollution into environment. Plenty of synthetic substances are used as sorbents for binding organic compounds (including the monoaromatic hydrocarbons) both from the surface and underground waters. The aim of this paper is to present results of the research on the possibilities of using the aspen poplar (Populus tremula L.) seeds as a sorbent of monoaromatic hydrocarbons from an aqueous solution. In order to increase sorption capacity, the seeds biomass was submitted for the process of mercerizing in diversified time and temperature in water and the NaOH so…
Development of a simulation chamber for the evaluation of dermal absorption of volatile organic compounds
2020
Abstract An exposition chamber has been designed and developed for the production of contaminated atmospheres with fixed and known concentration of volatile organic compounds. The proposed chamber has been evaluated for the determination of in-vitro diffusion parameters, such as flux and lag time for benzene, toluene, ethylbenzene, and xylenes (BTEX). Polydimethylsiloxane (PDMS) and Strat-M® membranes were evaluated, including the effect of membrane thickness, from 0.5 to 3.0 mm, on the diffusion parameters. The obtained flux values and lag times, ranged from 0.2 to 1.5 μg cm−2 h−1 and from 10 to 130 min, respectively, for studies performed at a BTEX concentration of 51 μg L−1 in air. Diffe…
Outdoor, indoor and personal distribution of BTEX in pregnant women from two areas in Spain - Preliminary results from the INMA project
2010
Volatile organic compounds (VOCs), which are habitually found in both outdoor and indoor environments, may represent a significant health risk. In this context, pregnancy is a critical period since foetuses are more vulnerable than adults to exposure to toxic compounds. The objective of this study is to present the preliminary results of a series of measurements of outdoor (O), indoor (I) and personal exposure (P) to benzene, toluene, ethylbenzene, o-xylene and m,p-xylene (BTEX) in 107 pregnant women from two areas in Spain, namely Valencia and Sabadell. BTEX samplers were installed for 48 hours both inside and outside of the women’s homes, along with personal samplers. In addition, the tes…
Use of semipermeable membrane devices for assessment of air quality in Tangier (Morocco)
2009
Semipermeable membrane devices (SPMDs) have been used for the evaluation of the contamination of air in both the urban and the industrial area in Tangier (Morocco). Benzene, toluene, ethylbenzene a...
Assessing air quality inside vehicles and at filling stations by monitoring benzene, toluene, ethylbenzene and xylenes with the use of semipermeable …
2007
BTEX (benzene, toluene, ethylbenzene, and xylenes) were used as target molecules to evaluate the quality of air inside motor vehicles and near filling stations, using semipermeable membrane devices (SPMDs) as low-cost passive sampling devices. A direct, fast, simple methodology based on the use of headspace-gas chromatography-mass spectrometry detection (HS-GC-MS) was developed for BTEX determinations, without any sample pre-treatment. SPMDs (25.4 cm2 surface, filled with 100 microL triolein) were employed as static samplers. After the selected deployment time, the SPMDs were heated inside a HS vial at 150 degrees C for 20 min and BTEX compounds were determined by GC-MS in selected ion moni…
Samplers for VOCs in air based on cyclodextrin–silica hybrid microporous solid phases
2012
Samplers for VOCs in air based on cyclodextrin-silica hybrid microporous solid phases are proposed. The solid phase preparation is very easy and inexpensive. Proposed samplers compared with other solid phases present the advantages of a wider range of operative conditions for VOCs desorption. Samplers are tested based on results for the determination of benzene, toluene, ethylbenzene and o-xylene, m-xylene and p-xylene (BTEX) in air. Operational parameters are optimized and quantitative recovery is obtained using a solid phase from 2-hydroxypropyl-β-cyclodextrin and acetonitrile as the extraction solvent. The recoveries obtained are 89 ± 4%, 90 ± 6%, 91 ± 2%, 87.0 ± 0.9%, 88 ± 4%, and 88 ± …
The possibilities of using broadleaf cattail seeds (Typha latifolia L.) as super absorbents for removing aromatic hydrocarbons (BTEX) from an aqueous…
2018
Sorption of oil-related products (including mainly the propellants) is the very basic process that counteracts spreading these types of pollution into environment. Plenty of synthetic substances (including the monoaromatic hydrocarbons) are both from the surface and underground waters. The aim of this study was to present the research’s results on the possibilities of using the broadleaf cattail (Typha latifolia L.) seeds as a sorbent of monoaromatic hydrocarbons from an aqueous solution. In order to increase sorptive capacity, the seeds biomass was submitted for the process of mercerizing in diversified time and temperature in water and the NaOH solution. The removal of benzene, toluene, e…
Comparative evaluation of liquid chromatography versus gas chromatography using a β-cyclodextrin stationary phase for the determination of BTEX in oc…
2009
An HPLC method for the determination of benzene, toluene, ethylbenzene and o-xylene, m-xylene and p-xylene in occupational environments was developed and compared with a GC-MS method. Chromatographic analysis using a beta-cyclodextrin stationary phase was performed after active and passive air sampling by adsorption on activated charcoal and pressurized fluid extraction. The analytes were completely separated and quantified using both methods, although GC-MS provided better resolutions and lower detection limits than HPLC. The HPLC method was unsuccessfully applied to the determination of benzene in real samples because its sensitivity was too low. Both methods were applied to the analysis …
Assessment of air passive sampling uptakes for volatile organic compounds using VERAM devices
2017
Abstract A calibration chamber has been designed and employed for the simple and easy determination of uptake sampling rate (RS) of volatile organic compounds (VOCs) from air using passive samplers. A flow of clean air was continuously spiked, at a constant VOC concentration, by the microinjection of a standard solution by means of a T-type tube. The developed system allowed the complete evaporation at room temperature of the standard solution in acetone and the air concentration of VOCs was easily controlled by the regulation of the clean air flow, the standard solution concentration and its flow. Active sampling was employed for monitoring the true concentration of the evaluated compounds…