Description of the Analysis of a Wide Range of Volatile Organic Compounds in Whole Air Samples Collected during PEM-Tropics A and B

Abstract

A large number of hydrocarbons, halocarbons, and organic nitrates were quantified in whole air samples acquired for the NASA-sponsored GTE missions PEM-Tropics A and B. The samples were collected in electro-polished stainless steel canisters from two aircraft while flying over the Pacific Basin. Two nominally identical multicolumn multidetector gas chromatographic analytical systems were employed. Whole air samples were also used as working and calibrated standards and were collected specifically for this purpose. This paper describes the analytical procedure employed during PEM-Tropics B. Minor differences in the PEM-Tropics A system will also be discussed. More than 3,900 samples were analyzed for 34 gases during PEM-Tropics A, over 4,500 samples were analyzed for 58 gases during PEM-Tropics B. An overview is presented of the collection, analysis, and quantification of whole air samples during the PEM-Tropics missions, along with an analysis of the analytical precision achieved during these missions.

A Winogradsky-based culture system shows an association between microbial fermentation and cystic fibrosis exacerbation

“…A modified bioreactor and analytical gas chromatography and mass spectrometry system was used for headspace gas collection (Umber et al, 2013), where replicates of six individual tubes were placed directly inside three separate glass collection containers (triplicate) and incubated at 37 1C for 24 h to collect headspace gas. Headspace gas was directly injected into a gas chromatography and mass spectrometry system and analyzed as described in , Shin et al (2009), Umber et al (2013) and Colman et al (2001). The area under the curve of selected volatile organic compounds was called manually and converted to partsper-trillion where possible for the quantification of gases.…”

“…Gas bubbles were not observed again until the onset of the second exacerbation event (Figure 3). A longitudinal sample that produced bubbles in WinCF tubes (day 195, Figure 3 and Figure 5) was inoculated into another set of capillary tubes and incubated for headspace gas collection and identification of volatile organic compounds (Colman et al, 2001). Of all the significantly elevated headspace gases detected from sputuminoculated tubes, acetaldehyde and dimethyl disulfide (DMDS) had the greatest fold increase compared with sterile tubes (permutation test, Supplementary Table S3) (Figure 4).…”

The production and persistence of ΣRONO<sub>2</sub> in the Mexico City plume

“…This measurement represents the sum of gas-phase HNO 3 and fine (submicron) aerosol nitrate. Hydrocarbons and C 1 -C 5 alkyl nitrates were measured by UC Irvine using gas chromatography of whole air samples (Colman et al, 2001). Oxygenated volatile organic carbon species (methyl-ethyl-ketone, methanol, ethanol, acetone and acetaldehyde collectively referred to, when combined with CH 2 O, as oxidized volatile organic carbon or OVOC) were measured by NASA Ames using gas chromatography (Singh et al, 1999).…”

Hydroxyl concentration estimates in the sunlit snowpack at Summit, Greenland

“…NMHCs, halocarbons, and alkyl nitrates were measured via a 3 GC system, described in Colman et al (2001). In 2003, the system employed a quadrupole mass selective detector (MSD), 2 flame ionization detectors (FIDs), and 2 ECDs.…”