Breath sampling

Pellizzari ED, Zweidinger RA, Sheldon LS. 1985b. Method 24. GC/MS determination of volatile halocarbons in breath samples. In Environmental Carcinogens selected methods of analysis. Fishbein L, O Neill IK, eds. Lyon, France. International Agency for Research on Cancer, 7 413-441. 

Hcxanc can be determined in biological fluids and tissues and breath using a variety of analytical methods. Representative methods are summarized in Table 6-1. Most methods utilize gas chromatographic (GC) techniques for determination of -hexane. The three methods used for preparation of biological fluids and tissues for analysis are solvent extraction, direct aqueous injection, and headspace extraction. Breath samples are usually collected on adsorbent traps or in sampling bags or canisters prior to analysis by GC. 

Raymer JH, Thomas KW, Pellizzari ED, et al. 1994. A breath sampling device for measuring human exposure to volatile organic compounds in microgravity. Aviation, Space and Environmental Medicine 353-360. 

Inhalation is the predominant route of exposure to 1,4-dichlorobenzene for the general population. According to data from the TEAM study, 1,4-dichlorobenzene was found in 44-100% of air and breath samples from several U S. locations, and indoor air levels were up to 25 times higher than ambient outdoor levels for dichlorobenzene (1,3- and 1,4-dichlorobenzene) (Wallace et al. 1986b). The EPA has estimated that adult exposure to 1,4-dichlorobenzene is about 35 g/day, based on a mean ambient air concentration of 1.6 g/m (0.27 ppb) (EPA 1985a). Inhalation exposure may be considerably higher indoors where 1,4-dichlorobenzene space deodorants or moth repellents are used. 

Breath samples are usually collected through a spirometer onto a sorbent cartridge (Barkley et al. 1980) or into passivated canisters (Thomas et al. 1991). Analytes are concentrated cryogenically from a portion of the canister contents or after thermal desorption from the sorbent, then analyzed by GC/MS. Recovery... 

Most of the alcohol distributes into body water, but like most solvents and anesthetics some distributes into fat. It is excreted in the urine and breath, hence the utility of taking breath samples to evaluate alcohol exposure. The majority of alcohol is metabolized in the liver. Alcohol dehydrogenase (ADH) metabolizes alcohol to acetaldehyde. Acetaldehyde is toxic, with elevated levels causing flushing, headache, nausea, and vomiting. Acetaldehyde is in turn quickly metabolized to the less toxic acetate by acetaldehyde dehydrogenase (ALDH) (Figure 3.1). 

Blood alcohol concentration (BAG) is often based not on an actual sample of blood but rather on the concentration of alcohol in a sample of breath (Figure 3.3). Alcohol is volatile, and, as described by Henry s law, there is a constant relationship between the amount of alcohol vapor found in a volume of air (breath sample) and the amount of alcohol found in a volume of liquid (blood). All breath-testing equipment uses the blood-breath ratio of 2,100 1 for alcohol. This means that the amount of alcohol found in 2,100 milliliters of breath is equivalent to the amount of alcohol found in 1 milliliters of blood. 

This ratio may vary from individual to individual and, under certain conditions, even within the same individual. Determination of a BAG from a breath sample may not always be accurate, and this is often a point of argument in the courtroom. 

Braden B, Haisch M, Duan LP et al (1994) Clinically feasible stable-isotope technique at a reasonable price - analysis of 13C02/12C02-abundance in breath samples with a new isotope selective nondispersive infrared spectrometer. Zeitschrift fur Gastroenterologie 32(12) 675-678... 

In large population-surveillance studies, such as those used by the Centers for Disease Control and Prevention (CDC), biomonitoring is usually conducted on urine and blood samples. However, in research investigations, other matrices—such as breast milk, cord blood, and breath samples—may be used. 

A simple method for the analysis of small volumes of gas from single-breath samples from humans was described by Zarling and Clapper (1987). Total breath samples were collected into a gas-tight bag and 50 ml aliquots withdrawn into polyethylene/polypropylene syringes. Alveolar breath samples collected by use of a Haldane-Priestly tube were also collected in this way. Gas samples were injected directly into the GLC via a gas-sampling valve. 

The rate constants for reaction of precursor ions H30", NO", and 02 " with different molecules were determined experimentally. To calculate the partial pressure of the analyte [M] it is necessary to know the value of constant k for each reaction and the concentration of [MEf. The method also allows simultaneous measurement of the concentration of several analytes. Studies have shown that ions such as HaO" and N react quickly enough with various organic compounds, but 02 " reacts quickly only with small molecules such as NO, NO2, or NH3. In the case of samples containing a large amount of moisture (e.g., breath samples or head-space of aqueous solution), cluster ions such as H30 (H20)i 2,3 may be formed in... 

Tests are no available that measure 1,1-dichloroethane in urine, blood, breath and body tissues. Because urine, blood, and breath samples are easily obtained, these samples are examined to determine if a person has been exposed to 1,1-dichloroethane. These tests are not routinely available at a doctor s office and would require special equipment for sampling and detection of the compound. Since most of the 1,1-dichloroethane that is taken into the body leaves within two days, these tests must be done soon after exposure occurs. Although these tests can confirm that a person has been exposed to 1,1-dichloroethane, it is not yet possible to use the test results to predict the type or severity of any health effects that might occur or the level of exposure that may have occurred. Because exposure to 1,1-dichloroethane at hazardous waste sites is likely to include exposure to other similar chemicals at the same time, levels of 1,1-dichloroethane measured through these types of medical tests may not reflect exposure to 1,1-dichloroethane alone. Information regarding tests for the detection of 1,1-dichloroethane in the body is presented in Chapters 2 and 6. 

Zweidinger et al. (1982) and Wallace et al. (1982) conducted a study of the levels of 1,1 -dichloroethane in the inhaled and exhaled air and drinking water of college students in Texas and North Carolina. Low levels (<0.49 ppb) of 1,1-dichloroethane were found in the personal air quality monitors of the Texas students, whose campus bounded a petrochemical manufacturing area, but none was detected in the exhaled breath samples. 1,1-Dichloroethane was not detected in the breathing zone air of the North Carolina students. 

Breath Collect human breath sample by means of a spirometer and analyze GC/MS Not detected No data Barkley et al. 1980... 

The RQ can be determined directly, by taking breath samples during the course of the day. However, this method of determining the RQ Is confining, and defeats... 

A more down-to-Earth use of fuel cells is found in traffic-law enforcement. Police officers need quick and simple ways to determine a person s blood alcohol level in the field. In the time it takes to bring a person to the station or to a hospital for a blood or urine test, the person s blood alcohol content (BAG) might change. Fuel cells, such as the one in the device shown above, provide a quick and accurate way to measure BAG from a breath sample. The alcohol ethanol from the person s breath is oxidized to acetic acid at the anode. At the cathode, gaseous oxygen is reduced and combined with hydronium ions (released from the anode) to form water. The reactions generate an electric current. The size of this current is related to the BAG. 

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