Addition of a fast GC to SIFT-MS for analyses of individual monoterpenes in mixtures

Soft chemical ionization mass spectrometry (SCI-MS) techniques can be used to accurately quantify volatile organic compounds (VOCs) in air in real time; however, differentiation of isomers still represents a challenge. A suitable pre-separation technique is thus needed, ideally capable of analyses in a few tens of seconds. To this end, a bespoke fast GC with an electrically heated 5 m long metallic capillary column was coupled to a selected ion flow tube mass spectrometry (SIFT-MS) instrument. To assess the performance of this combination a case study of monoterpene isomer (C10H16) analyses was carried out. The monoterpenes were quantified by SIFT-MS using H3O+ reagent ions (analyte ions C10H17+, m/z 137, and C6H9+, m/z 81) and NO+ reagent ions (analyte ions C10H16+, m/z 136, and C7H9+, m/z 93). The combinations of the fragment ion relative intensities obtained using H3O+ and NO+ were shown to be characteristic of the individual monoterpenes. Two non-polar GC columns (Restek Inc.) were tested: the advantage of MXT-1 was shorter retention times whilst the advantage of MXT-Volatiles was better temporal separation. Thus, it is possible to quantify components of a monoterpene mixture in less than 45 s by the MXT-1 column and to separate them in less 180 s by the MXT-Volatiles column. As an illustrative example, the headspace of three conifer needle samples was analysed by both reagent ions with both columns showing that mainly α-pinene, β-pinene and 3-carene were present.

The Foliar Endophyte Phialocephala scopiformis DAOMC 229536 Proteome When Grown on Wood Used as the Sole Carbon Source

The conifer needle endophyte Phialocephala scopiformis DAOMC 229536 was cultivated in medium containing ground Pinus contorta wood as the sole carbon source. Mass spectrometry analyses identified 590 proteins.

The foliar endophytePhialocephala scopiformisDAOMC 229536 secretes enzymes supporting growth on wood as sole carbon source

The conifer needle endophyte,Phialocephala scopiformis, was cultivated in media containing groundPinus contortawood as sole carbon source. After five and seven days growth, concentrated extracellular fluids were subjected to LC-MS/MS analyses. A total of 590 proteins were identified of which 99 were assigned to glycoside hydrolase families within the Carbohydrate Active Enzyme (CAzyme) system. Multiple isozymes of exo-and endo-acting cellulases were among the most abundant proteins, and oxidative degradation of cellulose was supported by the presence of lytic polysaccharide monooxygenases, glucooligosaccharide oxidase and cellobiose dehydrogenase. Oxidoreductases were also plentiful and included GMC oxidoreductases, alcohol dehydrogenases, laccases, copper radical oxidases, tyrosinases and catalase. The expression and diversity of extracellular oxidoreductases indicates a capacity to metabolize alcohols and aromatic compounds.