Analyzing Multiple Compounds in Human Breath in Real Time

Real Time Analysis of Multiple Compounds in Human Breath by Breath Analysis of Expired VOCs during Exercise Summary VOCs in Human Breath

By monitoring breath VOCs, analysis of physiological events could be undertaken in real-time in a safe, non-invasive manner. VOCs can be a marker for lactate threshold, and oxidative stress, but the analysis can prove a challenge to conventional ‘off-line’ gas analysis equipment due to the fast response times and wide dynamic range required.

Figure 1. The Hiden HPR-20 Transient MS

These issues can be overcome using the HPR-20 Transient MS, which tackles both of the above issues and is also equipped with a highly sensitive PIC detector. It can therefore measure compounds breath-by-breath, which is vastly superior to that offered by traditional ‘off-line’ techniques, along with other factors such as end tidal and breathing rate.

Figure 2. Example data showing the real-time analysis of muliple compounds exhaled in human breath during an exercise test.

Experimental Setup

The test used a group of subjects with various ages and fitness levels. They were set a maximal exercise test on a stationary bicycle, with the resistance of the bicycle being ramped up over time in order to push the subject to their aerobic capacity. During the test the subject was fitted with a proprietary breathing mask, which was in turn connected to the HPR-20 TMS via a customized adaptor that was optimized for high speed analysis.

Results

The set-up of the equipment allowed data to be collected and investigated in real-time during the experiment with multiple compounds being tracked as they were produced in varying amounts during aerobic and anaerobic respiration. With each data point only taking 20 ms to be analyzed, the subjects every breath could be monitored for concentration of compounds. Other physiological changes, such as lactate threshold were also able to be interpreted from the inflections in the data points. This rapid monitoring and analyses of VOC compounds during physiological events is novel and is not easily done via other methods.

The fast response of the HPR-20 Transient MS can be seen in Figure 2, as each breath is tracked. In contrast to conventional off-line techniques, parameters such as end tidal as well as breathing rate can be readily deduced.

Conclusion

• The Hiden HPR-20 TMS is demonstrably the perfect product for high speed, high sensitivity analysis of compounds in human breath.
• Real time analysis of exhaled species is a novel research tool.
• The excellent response time and dynamic range offered by the HPR- 20 allow the concentration changes of multiple compounds to be measured in real time.

This information has been sourced, reviewed and adapted from materials provided by Hiden Analytical.

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