• Meets specifications of U.S. EPA 325
  • 3.5 x 0.25-inch OD (sized for Perkin Elmer and Markes International Thermal Desorbers) stainless steel tube deactivated with SilcoNert® 2000
  • Pre-conditioned Carbopack® X or Anasorb GCB1 sorbent held between two 100-mesh stainless steel screens
  • Sealed with brass Swagelok^® screw caps with PTFE ferrules for transport
  • Diffusion cap
  • Unique identification number and bar code
  • Airflow direction and cap placement arrow indicators printed on tube
    


• Benzene uptake rate of 0.67 ml/min on Carbopack X sorbent
  
  
• Use to determine average benzene concentration in the range of 0.5 to 500 µg/m³ over a two-week periods
  
  
• Collected compounds are analyzed quantitatively using GC or GC-MS
  
  
• Reusable after laboratory conditioning
  
  
• Weatherproof tube shelter available
  
  
• Allows for extended sample times for low-level measurements
  
  
• Establish baseline/manage exceedances for benzene and other HAPs and VOCs. See Technical Note: Sampling Rates for Benzene and Other VOCs Using the SKC Passive TD Tube(PDF)

• Ideal for establishing average airborne concentrations of additional VOCs of concern

 

SKC Passive Thermal Desorption Tube Applications

• Fenceline Monotoring
• Indoor Air Sampling
• Vapor Intrusion Studies


 


 


 



 



 

Performance Profile

Sorbent	Carbopack X, Anasorb GCB1 (see Reference)
Tube Material	Stainless steel coated with SilcoNert 2000, sealed with brass Swagelok screw caps fitted with PTFE ferrules
Uptake Rate	Carbopack X: Benzene 0.67 ml/min Anasorb GCB1: Benzene 0.63 ml/min
Dimensions	3.5 x 0.25-inch OD (Sized for Perkin Elmer and Markes International Thermal Desorbers)
Analysis	GC-FID or GC-MS (EPA 325B)

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

 

Reference

McClenny, W.A. et al., “24 h Diffusive Sampling of Toxic VOCs in Air onto Carbopack X Solid Adsorbent Followed by Thermal Desorption/GC/MS Analysis–Laboratory Studies,” J. Environ. Monit., Vol. 7, Issue 3, 2005, pp. 248-256

Technical Note: Sampling Rates for Benzene and Other VOCs Using the SKC Passive TD Tube (PDF)

Federal Register, Vol. 80, No. 230, 40 CFR Parts 60 and 63, www.gpo.gov/fdsys/pkg/FR-2015-12-01/pdf/2015-26486.pdf

EPA Method 325A, Volatile Organic Compounds from Fugitive and Area Sources, (sampling), https://www3.epa.gov/ttn/emc/promgate/m-325a.pdf

EPA Method 325B, Volatile Organic Compounds from Fugitive and Area Sources, (analysis), https://www3.epa.gov/ttn/emc/promgate/m-325b.pdf

 

The SKC Passive TD Tube for Benzene meets specifications in U.S. EPA 325 (A and B) to comply with national emissions standards for hazardous air pollutants (HAPs) from petroleum refineries and specifically a new regulation to improve fugitive emissions management. EPA 325A requires time-integrated passive sampling to monitor volatile organic compounds (VOCs) at several points at refinery boundaries in conjunction with EPA 325B for analysis by thermal desorption-gas chromatography (TD-GC). The SKC Passive TD Tube is your media solution for refinery fenceline monitoring to determine the average concentration of benzene over the method-required two-week monitoring period.

EPA Method 325
EPA 325A requires refineries to deploy 12 to 24 passive samplers every two weeks to monitor benzene‡ concentration around the fenceline of each refinery. The total number of samplers to be deployed is based on refinery size. Benzene concentration on the samplers is monitored on an annual rolling average to determine the presence of significant excess fugitive emissions. Major source petroleum refineries in the U.S. have two years after promulgation of the rule to implement a sampling protocol. SKC Passive TD Tubes can be used initially to establish a baseline to help manage exceedances and then for compliance sampling once mandatory.

‡	While benzene is a primary target compound of EPA 325, the method can be used to screen average airborne concentrations of additional fenceline VOCs (including other HAPs). See Technical Note: Sampling Rates for Benzene and Other VOCs Using the SKC Passive TD Tube (PDF)

About SilcoNert 2000 (Siltek® /Sulfinert®)
SilcoNert 2000 is used as a coating to deactivate the stainless steel Passive TD Tube for Benzene. This process improves corrosion resistance, inertness, and hydrophobicity for better detection limits and system performance.

 

 

 

Operating Instructions - Passive Thermal Desorption Tubes 226-520 and 226-521 (PDF)

Passive TD Tube for Benzene Spec. Sheet (PDF)

Technical Note: Validated Uptake Rates for Benzene and Other VOCs Using the SKC Passive TD Tube (PDF)

226-520 Tube for BTEX and other VOCs Laboratory Reference List