Qualifications & Memberships
Master of Science
Doctor of Philosophy
New Zealand Institute of Chemistry (NZIC) (Professional Organisation): Fellow (FNZIC)
Royal Society of New Zealand (RSNZ) (Professional Organisation): Fellow (FRSNZ)
Research Interests
The enormous clouds of gas and dust that exist between the stars act as chemical factories producing vast quantities of a whole range of different chemical species. We are interested in how these chemicals are synthesised. The experimental techniques we have to investigate these processes include a flowing afterglow selected ion flow drift tube (FA-SIFDT) and an Ion Cyclotron Resonance mass spectrometer. Ion-neutral processes of specific interest are ion-atom reactions and the competition between bimolecular and termolecular association reactions. The sensitivity of the FA/SIFDT instrument has shown it to be capable of detecting trace chemicals in air down to the low ppb range. We have utilized this aspect of FA-SIFDT technology in a number of applications from medicine, environmental pollution and the detection of volatile organic compounds.
- Atmospheric chemistry
- Interactions of gaseous ions with neutrals and their applications to interstellar clouds, planetary atmospheres and combustion
- Ion-molecule reactions
- Selected ion flow tube mass spectrometry
- Trace gas analysis; medical and environmental applications
Recent Publications
- Langford VS., Billiau C. and McEwan MJ. (2020) Evaluation of the efficacy of SIFT-MS for speciation of wastewater treatment plant odors in parallel with human sensory analysis. Environments - MDPI 7(10): 1-33. http://dx.doi.org/10.3390/environments7100090.
- Smith D., McEwan MJ. and Španěl P. (2020) Understanding Gas Phase Ion Chemistry Is the Key to Reliable Selected Ion Flow Tube-Mass Spectrometry Analyses. Analytical Chemistry 92(19): 12750-12762. http://dx.doi.org/10.1021/acs.analchem.0c03050.
- Allpress C., Crittenden D., Ma J., McEwan M., Robinson S., Wilson P. and Wu M. (2019) Real-time differentiation of ethylbenzene and the xylenes using selected ion flow tube mass spectrometry. Rapid Communications in Mass Spectrometry 33(23): 1844-1849. http://dx.doi.org/10.1002/rcm.8550.
- Langford VS., Padayachee D., McEwan MJ. and Barringer SA. (2019) Comprehensive odorant analysis for on-line applications using selected ion flow tube mass spectrometry (SIFT-MS). Flavour and Fragrance Journal 34(6): 393-410. http://dx.doi.org/10.1002/ffj.3516.
- Langford VS., McEwan MJ., Askey M., Barnes HA. and Olerenshaw JG. (2018) Comprehensive instrumental odor analysis using sift-ms: A case study. Environments - MDPI 5(4): 1-9. http://dx.doi.org/10.3390/environments5040043.
