Tedlar bags

Exhaled air Collected in Tedlar bag injected into GC GC/ECD (both trichloro- ethylene and trichloro- ethanol) 5 ppb (trichloroethylene) 2 ppb (trichloro-ethanol) NR Monster and Boersma 1975... 

Figure 1 Schematic diagrams of (a) stainless steel air sampling canister and (b) Tedlar bag...

Air in the community was sampled for VOCs by Summa canister (8-hour orifice, and 7 m stainless steel frit filter) and for reduced sulfur gasses by Tedlar bag. These samples were 24 hour express mailed to Performance Analytical Inc. and analyzed as described above. Aerosols (PM2.s and PMi0)... 

A Tedlar bag, made of polyvinyl fluoride, was used. These bags were purchased from SKC, Inc. (US). 

Allene must not be allowed to condense in the reaction vessel prior to the introduction of the BBr3. Boron tribromide reacts rapidly and exothermically with liquid allene to give a black mixture that yields very little of the desired product. In one experiment in which the connection between the Tedlar bag and the reaction vessel... 

The olfactometer was calibrated using C02, as the odorous gas, diluted in air to 10000 ppm by volume, and contained in a 30 1 Tedlar bag (Fig. 5) (7). C02-free oxygen was used as the diluting gas. The C02 concentration was was sufficiently low to avoid significantly altering the density of the odorous air. The bag was connected by silicon rubber tubing to the rotameter inlets and the diluted gas mixture was sampled via a tube placed inside the nose-piece and analysed by an infra-red gas analyser, with an accuracy of greater than 1% (Fig. 5). 

Exhaled air (breath) Collection in Tedlar bag preconcentration by Tenax-GC thermal desorption HRGC/FID and HRGC/MS No data No data Krotoszynski et al. 1979... 

Elemental composition C 12.14%, 0 16.17%, Cl 71.69%. Phosgene can be analyzed by GC using FID or a balogen-specific detector or by GC/MS. Ambient air may be collected in a metal container placed in an argon bath or condensed into any other type cryogenically cooled trap. Alternatively, the air may be collected in a Tedlar bag. The sampled air may be sucked by a condensation mechanism into tbe GC column. 

Finlayson-Pitts, B. J., J. N. Pitts, Jr., and A. C. Lloyd, Comment on A Study of the Stability of Methanol-Fueled Vehicle Emissions in Tedlar Bags, Environ. Sci. Technol., 26, 1668-1670(1992). 

Calcium carbide desulfurization slag has a distinctive odor. Since pure acetylene is odorless, the odor must be produced by other trace constituents in the off-gases. A calcium carbide desulfurization slag sample from one ductile foundry was treated with water at a 1 1 solid-to-liquid ratio, and the gas was collected in a Tedlar bag for analysis by GC-MS. Several trace gases were identified, including arsine, divinyl sulfide (CHj-CH S, ethanethiol (ethyl mercaptan), methane, phosphine, and carbon monoxide. 

Air collected in a Tedlar bag 1 mL air directly injected onto GC (portable) for PID detection flow rate 20 to 50 mL air/min (NIOSH Method 3700, 1987). 

Air collected in Tedlar bag or glass bulb and directly injected onto a GC column for TCD detection. 

Air collected in Tedlar bag an aliquot of sample injected onto the GC column at ambient temperature determined by TCD or FID. 

Concerns for the VOC loss from water samples during transportation by air have been raised on occasion. Laboratory studies, however, have demonstrated that there is no discernable difference between VOC data obtained from analysis of water samples shipped by land and by air (Craven, 1998). The notion of unsuitability of air transportation for air samples collected in Tedlar bags is also common. However, if Tedlar bags are filled to 2/3 of their capacity, they survive air travel without leaking or bursting. 

A temperature blank placed with the samples inside the cooler is the best tool for determining the true temperature of the samples upon arrival to the laboratory. For samples that do not require refrigeration (Tedlar bags with air, water samples for metal analysis), coolers are still the best shipping containers because they are light and durable. 

There are two general approaches to sampling air, or vaporous emissions from stationary (stack) and mobile (automobile, truck, etc.) sources, for the laboratory determination of volatile analytes.1 Bulk vapor-phase samples can be taken in the field in various containers and transported to a remote or field laboratory for analysis. Containers used for bulk vapor-phase samples include flexible polyvinyl fluoride (Tedlar ) bags, evacuated glass or metal reservoirs, and thermally insulated cryogenic collection vessels. Alternatively, the volatile analytes can be separated from the main components of air in the field and just the analytes and their collection devices transported to the laboratory. The principal techniques used to separate volatile analytes from air in the field are cryogenic traps, impingers, and solid-phase adsorbents. 

Air (ambient) Sample collection in Tedlar bag Cryogenically trap thermally desorb GC/PID 0.5 ppb NR Kowalski et al. 1985... 

Air (occupational) Sample collection in Tedlar bag direct injection GC/PID (NIOSH Method 3700) 50 ppb NR NIOSH 1987... 

An apparatus suitable for human breath collection was described by Lemoyne et al. (1987). Subjects were allowed to breathe for 4 min through a mouth piece connected to a Rudolph Valve from a Tedlar bag (Analygas Systems Ltd., Scarborough, Ontario, Canada) containing hydrocarbon-free air. Atmospheric air was hushed from the lungs and an aliquot of exhaled air collected during the succeeding 2 min while the hydrocarbon-free air was inspired. Hydrocarbons were concentrated by a loop-concentrator similar to that previously described and then injected into the GLC. 

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