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Passive Thermal Desorption Tubes

The SKC Passive Thermal Desorption tubes offer an easy and accurate way to sample low-level VOCs over extended periods of time. They meet the requirements of EPA 325A regulation for fence-line monitoring of benzene at petroleum refineries with extended sample periods of 14 days. SKC supplies sampling rates for other VOCs for other applications. A weatherproof shelter is available for protecting samplers during outdoor sampling.

Diffusive Thermal Desorption Tubes
  • Meets specification of U.S. EPA 325A and UK HSE MDHS 104
  • EPA-validated sampling rates available for benzene, toluene, ethylbenzene, xylenes and many other VOCs
  • Allows for extended sample times for low-level measurements
  • Unique identification number and bar code
  • Airflow direction and cap placement arrow indicators printed on tube
  • Reusable after laboratory conditioning
  • Ideal for establishing average airborne concentrations of additional VOCs of concern

Applications include:

  • Fenceline monitoring
  • Indoor air sampling
  • Vapour intrusion studies

The tubes are standard-sized SilcoNert 2000® deactivated Stainless Steel Thermal Desorption tubes with Swagelock fittings; when they are deployed a diffusion cap is connected to one end. The diffusion cap works the same way as a front plate on a passive badge, and has a small screen inside which also keeps out particulates/insects.  SilcoNert 2000® is used as a coating to deactivate the stainless steel EPA 325 Passive TD Tubes for Benzene. This process improves corrosion resistance, inertness, and hydrophobicity for better detection limits and system performance. Tubes are deployed inside a custom-made shelter for outdoor use, which can hold up to 4 tubes at a time, and keeps them pointing diffusion-cap downwards.

Note: All tubes are conditioned and quality control tested to assure low background

Specifications
Tube Material    Stainless Steel coated with SilcoNert® 2000, sealed with brass Swagelok screw caps fitted with PTFE ferrules
Dimensions    89 x 6.35 mm (3.5 x 0.25 inch) OD
Analysis    GC-FID or GC-MS
Validated Uptake Rates
Compound    Carbopack X mL/min    Anasorb GCB1 mL/min #  
Benzene    0.67 ±0.06    0.63 ±0.07
Carbon tetrachloride    0.51 ±0.06    N/A
Chlorobenzene    0.51 ±0.06    N/A
3-Chloropropene    0.51 ±0.3    N/A
p-Dichlorobenzene    0.45 ±0.05    N/A
1,1-Dichloroethane    0.57 ±0.1    N/A
1,2-Dichloroethane    0.57 ±0.08    N/A
1,1-Dichloroethene    0.57 ±0.14    N/A
1,2-Dichloropropane    0.52 ±0.1    N/A
Ethylbenzene    0.46 ±0.07    0.50
Styrene    0.50 ±0.14    N/A
Tetrachloroethene    0.48 ±0.05    N/A
Toluene    0.52 ±0.14    0.56 ±0.06
1,1,1-Trichloroethane    0.51 ±0.1    N/A
1,1,2-Trichloroethane    0.49 ±0.13    N/A
Trichloroethene    0.50 ±0.05    N/A
m,p-Xylene    0.46 ±0.09    0.47 ±0.04
o-Xylene    0.46 ±0.12    0.47 ±0.04

# SKC Anasorb GCB1 is equivalent to Carbopack B/Carbograph 1.

Passive Thermal Desorption Tubes and Accessories
Description Pack Size Part Number  
SKC Passive TD Tubes *  

6.35 mm (1/4 inch) OD deactivated stainless steel tubes filled with pre-conditioned sorbent and supplied with diffusion caps and brass Swagelok screw caps with PTFE ferrules. Choice of sorbents:

Carbopack X, 400mg
Anasorb GCB1  , 400mg






10
10






226-520
226-521

  226-520 SKC Passive Thermal Desorption Tubes, 6.35 mm (1/4 inch) OD deactivated stainless steel tubes filled with pre-conditioned sorbent and supplied with diffusion caps and brass Swagelok screw caps with PTFE ferrules. 
Diffusion Caps 10 226-525   226-525 Diffusion Caps for Thermal Diffusion Tubes 
Swagelok Fittings for ¼ inch OD x 3½ inch L tubes, set of 2 Each P50291   P50291 - Swagelok Fittings for ¼ inch OD x 3½ inch L tubes, set of 2 
PTFE Ferrules, set of 2 Each P30121   P30121 - PTFE Ferrules, set of 2, for use with Thermal Desorption tubes 
PVC Shelter, with aluminium bracket for fenceline attachment. Can hold up to 4 tubes at a time, and keeps them pointing diffusion-cap downwards. 11.4 cm diameter x 14.0 cm height (4.5 x 5.5 inch) Each 226-526   226-526 Weatherproof Shelter for Thermal Diffusion Tubes, which can hold up to 4 tubes at a time, and keeps them pointing diffusion-cap downwards. 

* Tubes must be used within 30 days of conditioning
Equivalent to Carbopack B/Carbograph 1

Passive TD Tubes, 6.35 mm (1/4 inch) OD deactivated stainless steel tubes filled with pre-conditioned sorbent and supplied with diffusion caps and brass Swagelok screw caps with PTFE ferrules. Choice of sorbents

226-520/-521

Diffusion Caps

226-525

Swagelok Fittings for ¼ inch OD x 3½ inch L tubes, set of 2

P50291

PTFE Ferrules, set of 2

P30121

Weatherproof Shelter, which can hold up to 4 tubes at a time, and keeps them pointing diffusion-cap downwards

226-526

Documentation
Passive Thermal Desorption Tubes Instructions

Passive Thermal Desorption
Tubes Instructions