Decomposition of Terpenes by Ozone during Sampling on Tenax

Abstract

The ozonolytic decomposition of terpenes and terpenoids during sampling on Tenax is investigated in an artificial air system at ambient concentration levels. The detrimental effect of 8-150 ppbv ozone depends on the chemical structure of the compounds: saturated terpenoids such as 1,8-cineole, camphor, and bornyl acetate are unaffected by ozone. The terpenes and terpenoids which containing one C-C double bond are slightly decomposed in the order camphene < β-pinene ≈ myrtenal < α-pinene < sabinene ≈ citronellal. The compounds containing two or more double bonds are significantly decomposed in the order d-limonene ≈ citral < linalool < β-ocimene < terpinolene << α-terpinene ≈ β-caryophyllene. For α-pinene, sabinene and d-limonene, their ozonolysis products are found on the tubes: pinonaldehyde, 5-(1-methylethyl)bicyclo[3.1.0]hexan-2-one, and 3-(1-methylethenyl)-6-oxoheptanal. The analytical recoveries are significantly enhanced for many compounds when the sampling duration is reduced from 10 min to 30 s, explained by the time available for ozonolysis. A miniature ozone scrubber with multiple layers of MnO(2)-coated copper nets was developed and thoroughly tested. The optimal number of plies is found to be 8, which ensures quantitative recoveries for all test compounds except α-terpinene, β-caryophyllene, citral, and citronellal. The results that are reported here call into question previous data on terpenes and terpenoids and/or their oxidation products where measurements have been carried out without the prior removal of ozone.

Characterization of Secondary Organic Aerosol Precursors Using Two-Dimensional Gas Chromatography with Time of Flight Mass Spectrometry (GC×GC/TOFMS)

“…As noted in the introduction, removing oxidants, especially ozone, is critical to preserving monoterpenes in offline samples. Unfortunately, physical oxidant scrubbers/filters can cause losses of some terpenes, such as linalool and camphor (Calogirou, 1996 et al;Helmig, 1997).…”

“…REA is a sampling technique used for the measurement of micrometeorological fluxes of atmospheric species (Businger and Oncley, 1990;Ren et al, 2011). The REA was located at a height of 25 m on the instrumented towers at both To prevent these losses, oxidants must be removed from the air stream prior to concentration on the cartridge (Cao and Hewitt, 1994;Calogirou et al, 1996). The potassium iodide or sodium thiosulfate filter coating reacts with O 3 and other oxidants to remove them from the airstream.…”

“…The potassium iodide or sodium thiosulfate filter coating reacts with O 3 and other oxidants to remove them from the airstream. Without the use of an oxidant filter, Calogirou et al(1996) found that un-saturated terpenes with one double bond (e.g. α-pinene, sabinene) exhibited moderate losses (5-35%) due to O 3, and those with two or more double bonds (e.g.…”

Biogenic volatile organic compounds at Azusa and elevated sites during the 1997 Southern California Ozone Study

“…To prevent ozone from reacting with the biogenic nonmethane organic compounds (NMOC) and their atmospheric reaction products in the adsorbent during sampling, an ozone scrubber [Hoffmann, 1995;Calogirou et al, 1996;Helmig, 1997] consisting of eight copper plyes coated with manganese dioxide (Dasibi Corp.), and constructed according to Calogirou et al [1996], was placed in front of the first sampling tube. Each scrubber was tested by pumping ozone (250 ppbv) through the scrubber and monitoring the mixing ratio with an ozone monitor (Dasibi Corp.).…”

Diffusive Uptake Rates of Volatile Organic Compounds on Standard ATD Tubes for Environmental and Workplace Applications

“…We found a low UR eff for α-pinene and treated it as an outlier and excluded it from Model (1) fitting. The low UR eff of α-pinene might be caused by decomposition on Tenax during sampling [42] and storage [43]. We also excluded hexanal as the relationship between log 10 Vg and BP was not established for aldehydes due to lack of data [35].…”