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Porous polymer sorbents are suitable for a wide range of applications but can exhibit high artifact levels. In addition certain polymers (i.e. Chromosorb, Porapak, HayeSep) exhibit significant batch to batch variations in total artifact levels and can self-generate aromatic hydrocarbons over time. These sorbents are therefore generally unsuitable for trace-level monitoring. However, most porous polymer sorbents are inert making them suitable for the analysis of labile and reactive compounds such as mercaptans and CS gas. Moreover, their hydrophobic nature allows them to be used for sampling in humid conditions.
Tenax TA is a general purpose sorbent used in several air monitoring and occupational hygiene applications. It is the most thermally stable of the porous polymers but will still benefit from being used at as low a temperature as possible for the application to minimise artifacts.
Tenax GR contains 23% graphitized carbon as an integral part of the material (the graphitized carbon is co-precipitated with the Tenax polymer). For some compounds Tenax GR offers slightly higher breakthrough volumes.
Porapak porous polymers are available that vary both in strength (specific surface area) and polarity. The two most commonly used in thermal desorption applications are Porapak N (weaker) and Porapak Q (stronger).
There are several Chromosorb Century series porous polymers varying in strength and polarity. The two most commonly used in thermal desorption applications are Chromosorb 102 (weaker) and Chromosorb 106 (stronger).
HayeSep polymers were developed to exhibit less bleed and shrinkage than other porous polymers. HayeSep D is the strongest sorbent in this series. However, it’s use tends to be restricted to very specialised applications e.g. chemical agent monitoring
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