Markes’ UNITY thermal desorber used to identify stress-induced changes in breath
Thursday, 28 March 2013 at 4:53:PM
A new study, published in the Journal of Breath Research, has shown that psychological stress results in changes in the levels of breath volatiles, which could have implications for the use of breath monitoring in disease diagnosis.
The work, carried out by Paul Thomas and colleagues at Loughborough University, involved monitoring the breath VOCs of 22 adults, both while listening to relaxing classical music and while performing a stressful mental arithmetic test. A face mask was used to collect the breath volatiles onto a two-bed sorbent tube from Markes, followed by analysis using a UNITY thermal desorber and GC/MS.
Six stress-sensitive compounds were identified, with levels of 2-methylpentadecane and indole observed to rise in response to stress. The abundances of four other compounds fell, which the researchers say may be due to ventilation effects.
Helen Martin is one of the authors of the paper, and played a key role in the study as part of her Ph.D. before joining the Technical Support team at Markes. She says that the rising use of breath volatiles to diagnose disease makes it important to understand how other factors may affect the VOC profile.
“Breath monitoring as a diagnosis tool is rapidly gaining acceptance, as it can help avoid the need for invasive tests”, she says. “However, in order to be able to know that a raised level of a compound in breath is indicative of say, diabetes, you first need to be sure that the same compound doesn’t result from the patient simply having a stressful drive to the hospital”.
Helen also provides some insights into what’s involved in carrying out this sort of work. “One of the main challenges is representatively sampling the wide range of trace-level compounds found in breath. This was where Markes’ systems came in really useful, with the backflush capability of UNITY meaning that we could extend the analyte range by using two sorbents in our sampling tubes and in the cold trap.
Helen says the fact that sorbent tubes can be analysed off-line is a big advantage. “When taking biological samples from people, it’s of great benefit to do the analysis in batches, as this avoids having to synchronise slots on your busy GC/MS instrument with the availability of participants”, she says. “However, you don’t want to be worrying about damage to the samplers or analyte loss during sample transport or storage, and on this front sorbent tubes have the edge over other sampling techniques”.
Helen continues to find her time at Loughborough University really useful in her day-to-day work. “Helping customers with their sorbent-tube sampling is a key aspect of my role as Technical Support Specialist at Markes, and I often find that I’m drawing on my Ph.D. experience when advising them on getting the best results from their own application”.
Read more about the research on the Loughborough University website and in LCGC.
The effect of a paced auditory serial addition test (PASAT) intervention on the profile of volatile organic compounds in human breath: A pilot study
M.A. Turner, S. Bandelow, L. Edwards, P. Patel, H.J. Martin, I.D. Wilson and C.L.P. Thomas, Journal of Breath Research, 2013: 017102.