Adsorbent Resins are utilized by Purge and Trap (P& T) and other thermal desorption applications. A wide variety of adsorbent resins are available from many suppliers and manufacturers. The following section describes the various resins available, their physical properties and where they can be obtained.
Tenax® TA is a porous polymer based on 2,6-diphenylene oxide. It has been specifically designed for the trapping of volatiles and semi-volatiles from liquid or solid matrices. Both the EPA and NIOSH specify the use of Tenax in their standard methods. Tenax TA is a low bleeding material with a low level of impurities. Due to its low affinity for water, Tenax TA is especially useful for the purging of volatile organics from high moisture content samples including the analysis of volatiles organics in water. Available from Scientific Instrument Services.
Tenax® GR is a composite material of Tenax TA and 30% graphite. The resulting material gives a higher breakthrough volume for most volatile organics, yet still has a low affinity for water. In addition Tenax GR maintains its high temperature stability to 350 degrees C. These properties make Tenax GR an ideal adsorbent for the trapping of volatiles from air, water and solid matrices. Due to its low affinity for water, Tenax GR is especially useful for the purging of volatile organics from high moisture content samples including the analysis of volatiles organics in water. Available from Scientific Instrument Services.
Carbotrap graphitized carbon blacks are ideal adsorbents for trapping a wide range of airborne organic compounds from butane/pentane hydrocarbons through the PCB's. It is usable to 400 degrees C and due to its coarse mesh size will provide minimal backpressure in the desorption tubes. Manufactured by Supelco.
Carbotrap C graphitized carbon blacks is an ideal resin for the trapping of a wide range of organic volatiles. It also has a coarse mesh size and can be used to 400 degrees C. Manufactured by Supelco.
Carboxen 569 is a carbon molecular sieve which is ideal for the trapping of the smaller organic analytes. It has a low affinity for water and can be used to trap many C2-C5 volatile organics. It is often used in conjunction with Tenax TA to produce mixed bed resins. Manufactured by Supelco.
Carbosieve SIII is a carbon molecular sieve that has the greatest ability for the trapping of the low molecular weight organics due to its large surface area.
Glass Beads are most useful for the trapping of large molecular weight compounds. It will not retain any of the light volatiles, aromatics or other medium boilers. Therefore it is most frequently used in mixed bed applications with other adsorbent resins. Available from Supelco.