Ozone Artifacts and Carbonyl Measurements Using Tenax GR, Tenax TA, Carbopack B, and Carbopack X Adsorbents

Abstract

Four popular thermally desorbable adsorbents used for air sampling (Tenax TA, Tenax GR, Carbopack B, and Carbopack X) are examined for the potential to form artifacts with ozone (O 3 ) at environmental concentrations. The performance of these adsorbents for the ketone and aldehyde species identified as O 3 -adsorbent artifacts was also characterized, including recovery, linearity, and method detection limits (MDLs). Using gas chromatography/mass spectrometry, 13 different artifacts were identified and confirmed for both Tenax TA and Tenax GR, 9 for Carbopack B, but none for Carbopack X. Several O 3 artifacts not reported previously were identified, including: pentanal, 3-hexanone, 2-hexanone, hexanal, 3-heptanone, and heptanal with Tenax TA; pentanal, 3-hexanone, 2-hexanone, hexanal, and 3-heptanone on Tenax GR; and 1-octene and 1-nonene with Carbopack B. Levels of straight-chain aldehyde artifacts rapidly diminished after a few cycles of adsorbent conditioning/O 3 exposure, and concentrations could be predicted using a first-order model. Phenyl-substituted carbonyl artifacts (benzaldehyde and acetophenone) persisted on Tenax TA and GR even after 10 O 3 exposure-conditioning cycles. O 3 breakthrough through the adsorbent bed was most rapid in adsorbents that yielded the highest levels of artifacts. Overall, artifact composition and concentration are shown to depend on O 3 concentration and dose, conditioning method, and adsorbent type and age. Calibrations showed good linearity, and most compounds had reasonable recoveries, for example, 90 Ϯ 15% for Tenax TA, 97 Ϯ 23% for Tenax GR, 101 Ϯ 24% for Carbopack B, and 79 Ϯ 25% (91 Ϯ 9% for n-aldehydes) for Carbopack X. Benzeneacetaldehyde recovery was notably poorer (22-63% across the four adsorbents). MDLs for several compounds were relatively high, up to 5 ng. By accounting for both artifact formation and method performance, this work helps to identify which carbonyl compounds can be measured using thermally desorbable adsorbents and which may be prone to bias because of the formation of O 3 -adsorbent artifacts.

Investigation of volatile organic compounds in office buildings in Bangkok, Thailand: Concentrations, sources, and occupant symptoms

“…The sorbent tube incorporated a 0.5 m long copper tube with a coated inner surface and potassium iodine as an ozone trap. This was used to prevent ozone artifacts forming with Tenax resin [28]. Personal sampling pumps (224-PCXR 4, SKC Inc., USA) were used to draw air at a flow rate of 40 ml min À1 .…”

Estimations of isoprenoid emission capacity from enclosure studies: measurements, data processing, quality and standardized measurement protocols

“…In particular, the polymeric adsorbent Tenax has been shown to react with ozone and NO 2 resulting in formation of artifacts (Clausen and Wolkoff, 1997;Klenø et al, 2002;Lee et al, 2006;McClenny et al, 2002). Apart from reactions of air pollutants with polymer molecules, oxidation of sampled BVOC can occur on adsorbent surface.…”

“…For instance, sampling at an ambient ozone concentration of 50 nmol mol −1 led to complete loss of highly reactive β-caryophyllene, but only to a minor loss of the less reactive limonene (Fuentes et al, 2000). Surface-oxidation of sampled BVOC molecules has been observed for both Tenax (Calogirou et al, 1996;Lee et al, 2006) and carbonbased adsorbents (Carbopack B, Carbosieve III etc.) (Fig.…”

“…(Fig. 4, Bates et al, 2000;Calogirou et al, 1996;Lee et al, 2006;McClenny et al, 2002;Palluau et al, 2007;Pellizzari and Krost, 1984;Pollmann et al, 2005). Although it has been stated that decomposition of BVOC is less of a problem on carbon-based adsorbents (Larsen et al, 1997), Pollman et al (2005) observed that some reactive sesquiterpenes were decomposed to a similar degree whether trapped on Tenax TA, Tenax GR, or Carbotrap C and Carbotrap B (previously marketed as Carbotrap).…”

An aircraft gas chromatograph–mass spectrometer System for Organic Fast Identification Analysis (SOFIA): design, performance and a case study of Asian monsoon pollution outflow

“…Problems from co-collection of ozone have been recognized previously (Goldan et al, 1995) and are documented in several studies (Bates et al, 2000;Plass-Dülmer et al, 2002;Pollmann et al, 2005;Lee et al, 2006;Apel et al, 2008;Arnts, 2008;Hellen et al, 2012). The ozone interference can be either positive via artefact formation from reaction with ozone in the sampling system (e.g.…”