Examples of breath monitoring

Urinary metaboUtefs) Mandelic acid (MA), Phenvlelvoxvlic acid (PA) Trichloroacetic acid (TCA) 

Pulmonary elimination half-lives (T,n) 13-52 min 4-20 hr 3 days 15 ntin 4 hrs 4 days 

BEI (1998) End-exhaled air Blood Not recommended 0.55 mg/L end-of-shift 0.02 mg/L prior-to-next-shift 10 ppm end-of-shift, after at least 2 shifts 1 mg/L end-of-shift, after at least 2 shifts 

Urine MA=800 mg/g creatinine, end-of-shift MA=300 mg/g creatinine, prior-to-next-shift PA=240 mg/g creatinine, end-of-shift PA=100 mg/g creatinine, prior-to-next-shift TCA=7mg/L 

A number of field studies have been published with similar designs, in which breathing zone air, blood, breafli and urine were measured in groups of workers. In addition, chamber studies allowed measurements under predetermined consistent conditions. The emerging patterns formed die basis for recommendations for biologic monitoring. 

In a study of thirty two workers, end-exhaled air was measured at the beginning of the first shift of the week, after 15-30 min after the end of the shift on the 3 and 5 day of the same week, and at the beginning of the first shift of the subsequent week. The authors required the subjects to hold their breaths for 5 seconds and collected only the last part of the breath to obtain alveolar air. These measurements correlated with personal breathing zone samples collected each day. The highest correlation was found between PERC and TCA in blood at the end of the workweek and the average exposure for the entire week (R =0.953). Among the non-invasive techniques, PERC in exhaled air collected 15-30 min after the end of the shift at the end of the week had an of 0.931, and was followed by TCA in urine 

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Many bioactive molecules have absorption bands in the infrared, which are accessible by existing infrared lasers or OPOs (Fig. 10.50). When enhancement cavities and cavity ringdown or cavity leak out spectroscopy are used detection sensitivities down into the ppb or even ppt range can be achieved [1545], This is important for sensitive measurements of breathing gases, where the composition of the exhaled gas gives information about possible diseases. One famous example is the presence of the bacteria Helicobacter pylori in the stomach, which can cause gastritis or even stomach cancer. Their presence and concentration can be monitored by the spec-... 

Next to exhaled breath analysis, PTR-MS can be a useful tool for monitoring the VOC fingerprint from microbial culture and incubated tissue cultures [37,38]. Different microbial cell cultures are known to produce characteristic VOC signatures that can be further used to identify the presence, for example, of microbial contamination of food. The advantage of this technique is that the emission of VOCs can be monitored on-line, which ultimately leads to a rapid screening procedure in microbiology and medicine. 

Breath diagnostics involve the analysis of a human breath sample to monitor, diagnose, and detect diseases and conditions. Exhaled breath contains a complex mixture of nitrogen, oxygen, carbon dioxide, water, and trace amounts of various volatile organic compounds hke NO, acetone, isoprene, and ammonia. Many of these species are formed as the by-products of metabohc processes and can be used as biomarkers for various diseases. Examples of such biomarkers are acetone for diabetes mellitus (type I), ammonia for renal disease, NO for asthma, etc. 

The PTR-MS has been developed and used for a number of different applications. For example, Lindinger, Hansel and Jordan (1998) described the monitoring of metabolic processes in the human body by analyzing breath the monitoring of fruit and meat aging and the decay of vegetation. This monitoring is done by PTR-MS analysis of VOCs emitted, and the analysis of trace components of ambient air. Crutzen et al. (2000), Wameke et al. (2001), Williams et al. (2001), and Poschl et al. (2001) described measurements made by PTR-MS from an aircraft over the tropical rainforests of Surinam. 

Some perchlorates have other, more limited, uses. For example, potassium perchlorate was previously used to treat Graves disease, a condition in which the body produces too much thyroid hormone. It is still used to monitor the production of thyroid hormones. Potassium perchlorate is also used in emergency breathing equipment for high altitude aircraft and underwater boats. Other uses of perchlorates include ... 

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