To date, a number of researchers have put forward that isoprene may be used as a marker in human breath for blood cholesterol. As the use of isoprene is a non-invasive technique, it could be a fast technique to determine the changes in blood cholesterol levels in individuals.
As the participant exercises, isoprene is washed from the muscles, suspected to be via the pulmonary gas exchange process. It is then exhaled and the process can be charted with an initial rise in expired concentration, followed by a drop and plateau.
The Hiden HPR-20 QIC Transient MS
For this test the HPR-20 QIC Transient MS was used and proved to be ideal due to its fast response, wide dynamic range and high sensitivity. It was coupled with a breathing mask that was modified with a heated Quartz Inlet Capillary (QIC).
The test itself comprised of a minute at rest, followed by 5 minutes of gentle exercise on a stationary bicycle, and then a further 5 minutes rest. This was well below maximum exertion for the subjects that were of a variety of ages and fitness levels, and were allowed to control the resistance of the bike to control the perceived effort level.
As can be seen from the graph, the initial level of isoprene was ~50 ppbv. Figure 1 then shows the ‘washing out’ of the isoprene from the muscles as it increases to around 200 ppbv. There is then a decrease to a stable value that is below the initial level, implying that the levels of isoprene in the blood did not rise back to the level seen during the first rest period. After another hour of rest it returned to the original level.
Figure 1. Trend data showing the change in isoprene concentration in expired breath during a submaximal exercise test.
Figure 2 shows the quick response times of the HPR20 Transient MS which could analyze each breath in real-time. This allowed end tidal, as well as breathing rate, to be deduced. This is a great improvement over online measurements that cannot offer this level of detail.
Figure 2. MASsoft v7 Data showing breath by breath isoprene levels during an exercise test.
- Real time analysis of exhaled isoprene is proven to be viable.
- The Hiden HPR-20 QIC TMS is demonstrably the perfect product for high speed, high sensitivity analysis of compounds in human breath.
This information has been sourced, reviewed and adapted from materials provided by Hiden Analytical.
For more information on this source, please visit Hiden Analytical.