Breath ammonia levels in a normal human population study as determined by photoacoustic laser spectroscopy

Abstract

Photoacoustic laser spectroscopy was used as a technique to measure real-time levels of ammonia in exhaled human breath in a small, locally recruited, normal healthy population (n = 30). This yielded an average level of breath ammonia of 265 ppb, ranging from 29 to 688 ppb. Although average levels were marginally higher in male volunteers, this was not statistically significant. In addition, no correlation could be found between age, body mass index, or breath carbon dioxide levels. Monitoring of the daily routine of two individuals showed a consistent decrease in oral breath ammonia concentrations by the early afternoon (post-prandial), but was followed by a gradual increase towards late afternoon. However, in a comparison of oral and nasal breath in two volunteers, nasal breath ammonia levels were found to be significantly lower than oral levels. In addition, the daily variation was only seen in oral rather than nasal measurements which may indicate that significant background levels are predominantly of oral origin and that nasal sampling is the preferred route to eradicate this background in future studies. These results provide a healthy human breath ammonia baseline upon which other studies may be compared.

The Measurement of Ammonia in Human Breath and its Potential in Clinical Diagnostics

“…This oral malodour is mostly due to byproducts of microbial metabolism, principally sulphur and nitrogen compounds, including ammonia (Amano et al, 2002). Several studies have shown that oral bacteria contribute to ammonia levels measured in breath (Hibbard and Killard, 2011;Smith et al, 2008;Wang et al, 2008). In order to measure the correlation between blood ammonia and breath ammonia relating to physiological processes and not to bacteria in the mouth, antibacterial mouth rinses have been used (Solga et al, 2013).…”

“…However, due to the challenges and complications associated with blood ammonia sampling, there has been a significant increase in interest in other sample matrices in which to measure ammonia (Metz, 2014). In particular, there has been major development in the field of breath ammonia measurement (Hibbard and Killard, 2011). Exhaled human breath typically consists of nitrogen (78.6%), oxygen (16%), carbon dioxide (4.5%), inert gases and volatile organic compounds (VOCs) (0.9%) (Tortora, 2006).…”

“…These have mostly been imstrumental techniques including chemical ionisation, gas chromatography-mass spectrometry (GC-MS) (Davies et al, 1997;Van den Velde et al, 2008), selected ion flow tube mass spectrometry (SIFT-MS) (Davies et al, 1997;Enderby et al, 2009;Turner et al, 2006), laser spectroscopy and laser photoacoustic spectroscopy (LPAS) (Hibbard and Killard, 2011;Lewicki et al, 2011;Navas et al, 2012;Popa et al, 2011;Wang et al, 2011). However, most of the developed instrumental techniques are typically complex, expensive and not suitable for diagnostic application.…”

“…However, some have now demonstrated effective application in human clinical studies (Hibbard et al, 2013). Several reviews are available on ammonia measurement techniques (Davies et al, 2014;Hibbard and Killard, 2011;Spanel and Smith, 2011). However, this is not the focus of this review.…”

Fotoakusztikus spektroszkópia alkalmazási lehetőségei a kilélegzett levegő gázösszetételének vizsgálatában

“…Különböző élettani és orvosi kutatásokhoz fotoakusztikus spektroszkópiai elven alapuló gázkoncentráció-mérőket is alkalmaztak már [39][40][41]. [49].…”