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Air Pollution: Monitoring
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Air Quality and Energy Systems, 2020
A measured volume of sample air is drawn or forced through a sorbent tube. Provided suitable sorbents are chosen, benzene is retained by the sorbent tube and thus is removed from the flowing air stream. The collected benzene (on each tube) is desorbed by heat and is transferred by inert carrier gas into a gas chromatograph equipped with a capillary column and a flame ionization detector or another suitable detector, where it is analyzed. Prior to entering the column, the sample is concentrated either on a cryo trap, which is heated to release the sample into the column, or on a pre-column, where higher boiling hydrocarbons are removed from the pre-column by back flush. Two general types of instruments are used. One is equipped with a single sampling trap and the other is equipped with two or more traps. The single-trap instrument samples for only part of the time in each cycle, whereas the multitrap instrument samples continuously. Typical cycling times are between 15 min and 1 hr.[35]
Personal Environmental Exposure Sensors and the Internet of Things
Published in Kirk A. Phillips, Dirk P. Yamamoto, LeeAnn Racz, Total Exposure Health, 2020
For analysis of gases with low concentrations of organic analytes (low parts-per-billion range), conventional methods include using a sorbent tube to collect and preconcentrate the sample. A thermal desorber then desorbs the sample from the sorbent tube before the sample is pumped to the column. Several researchers have made advances in miniaturizing preconcentrator technology, which removes the requirement for the sorbent tube and thermodesorber (Tian et al. 2005, Camara et al. 2011, Akbar et al. 2013, Bourlon et al. 2016). One of the first micro-preconcentrators was a micro hot place coated with a surfactant template sol–gel adsorbent (Manginell et al. 2000). Another approach came from Bourlon et al. (2016) who developed a micro-preconcentrator on a silicon chip measuring 8 mm × 21 mm with an inlet and outlet etched only 400 μm deep.
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Published in Neil McManus, Safety and Health in Confined Spaces, 2018
Neil McManus, Robert E. Henderson
Sorbent tube sampling utilizes the same concepts as dosimeter badges: absorption or adsorption of contaminants into or onto a sorbent medium. Sorbent tube sampling offers a number of additional refinements. The sorbent is loaded into sealed glass tubes that resemble short straws. A number of sorbent media, each with different properties, are available. (The medium is selected to optimize absorbence or adsorbence for a specific contaminant.) To sample, the ends are broken off and the tube is inserted into a manifold. Instead of relying on passive diffusion, this methodology utilizes a precision low-flow sampling pump to pull a calibrated volume of air through the tube over a specific interval of time. Some manifolds can accommodate several tubes simultaneously, each with an independently adjusted flow rate for concurrent sampling. On completion of sampling, the tubes are removed from the manifold, capped, and sent to a laboratory for analysis.
Particle-phase collection efficiency of the OVS and IFV Pro personal pesticide samplers
Published in Journal of Occupational and Environmental Hygiene, 2021
Shaunae Alex, Matthew Sovers, Patrick T. O’Shaughnessy
The IFV Pro sampler is equipped with a scaled IOM-style sampling head with a 11-mm inlet containing a 25-mm cassette facing horizontally followed by a sorbent tube housed in a hard plastic tube held vertically (Supplementary material, Figure S3). To prevent rapid breakthrough of the sorbent tube, the IFV Pro operates at a flow rate of 1 L min−1. To achieve a particle aspiration efficiency that matches the inhalable criterion while operating at that flow rate, the sampling head was developed as a scaled version of the IOM using methods developed by Vincent and his collaborators (Brixey et al. 2002; personal communication with the manufacturer). When collecting both particle and vapor phase, a separate filter sampling cassette (No. 225-4903, SKC, Inc., Eighty Four, PA) and 6 × 110 mm XAD-7 sorbent tube (No. 226-95, SKC, Inc., Eighty Four, PA) were used as directed by the manufacturer (SKC 2021) for each sample of ethylene glycol as further explained below. Analysis of the sorbent tube was performed in accordance with NIOSH Method 5523 (ALS Labs, Salt Lake City, Utah).
Work environment and occupational risk assessment for small animal Portuguese veterinary activities
Published in Journal of Occupational and Environmental Hygiene, 2018
Angela C. Macedo, Vânia T. Mota, João M. Tavares, Osvaldo L. Machado, Francisco X. Malcata, Marinela P. Cristo, Olga N. Mayan
The aforementioned five clinics were also used to assess occupational exposure to disinfectants. All products used to disinfect, clean, and shine are alkaline compounds. Note that all workers wore gloves during the application of these products, and, therefore, this study did not assess the dose of dermal exposure. In addition to alkaline compounds, Mentaback composing of 47.5% (v/v) ethanol, 25% (v/v) 2-propanol, 25% (v/v) butanol, and 2.5% (v/v) glutaraldehyde is also used but only in the surgery room area due to its bactericidal, fungicidal, virucidal, and sporicidal properties. In this study, the air concentration of glutaraldehyde during the disinfection period of the surgery room was quantified. Only one worker (nurse or technician at each clinic) performs this activity (less than 5 min) with the door closed. Personal air samples were collected using a solid sorbent tube (previously impregnated with a derivatizing solution) connected to battery-powered air sampling pumps (Aircheck 2000, SKC, Ambicontrol, Lisboa, Portugal), operated at a flow rate of 200 mL/min. The air samples were collected and analyzed according to the National Institute for Occupational Safety and Health (NIOSH) 2532 method.[20] The instrumental technique consisted of High Pressure Liquid Chromatography with UV detection (Thermo Finnigan UV2000, SpectraLab Scientific, Ontario, Canada).