Biomedical Engineering Reference
In-Depth Information
8.1.9 Case Study
8.1.9.1 Human Breath
Breakthrough of VOCs found in breath, guide to its use in the diagnosis of dis-
eases, disorder, and metabolic learning. Breath can be analyzed without analytical
instruments, i.e., exhaled breath VOC chemicals defined the symptoms of diabetes,
asthma, COPD, bronchiectasis, and lung diseases related to the respiratory system.
Breath analysis is an easy process, which does not have pain or embarrassment
related with blood and urine analysis. However, breath analysis has the problem
that it contains more water content in preconcentration sampling and detection of
substances. VOCs are acquiesed of core metabolic processes while inorganic
molecules are related to health conditions and can mimic a probable disease of the
individual or a recent exposure to a drug or an environmental pollutant. Therefore,
the abnormality in the concentration of certain trace gases, so-called biomarkers,
could provide clues to diagnose corresponding diseases.
The exhaled human breath is a mixture of N 2 ,O 2 ,CO 2 ,H 2 O, inert gases, and
thousands of other trace gases. These gases include inorganic molecules such as
NO, NH 3, or CO, and volatile organic compounds (VOCs) such as acetone,
methanol, or isoprene, with concentrations ranging from ppb to ppm as shown in
Table 8.5 . Example of taking breath sampling from human breath using sampling
system is shown in Fig. 8.1 .
There are various techniques by which breath can be analyzed as in GC and its
types are (1) Mass Spectroscopy (MS), (2) Flame-Ionized Detection (GC-FID),
(3) Ion Mobility Spectroscopy (IMS), and (4) Electrolyzer powdered flame ioni-
zation. Table 8.6 lists breath molecules origin and Table 8.7 summarizes bio-
markers and their respective physiological concentration ranges in the human
breath.
Table 8.5 Exhaled breath molecules concentration
Concentration
Molecule
Percentage
Oxygen, water, carbon dioxide
Parts-per-million
Acetone, carbon monoxide, methane, hydrogen, isoprene,
benzene methanol
Parts-per-billion
Formaldehyde, acetaldehyde, 1-pentane, ethane, ethylene,
other hydrocarbons, nitric oxide, carbon disulfide, methanol,
carbonyl sulfide, methanethiol, ammonia, methylamine,
dimethyl sulfide, benzene, naphthalene, benzothiazole, ethane, acetic aide
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