Breath collection

Breath Collect air from breathing zone using a midget impinger containing calcium hydroxide-calcium sulfide-arabinogalactan slurry add solution of A/iV-dimethyl-p-phenylenedi-amine and ferric chloride. Spectrophotometry 0.20 pg/m3 80 NIOSH 1977... 

Breath Collect on Tenax GC cartridge dry over calcium sulfate desorb thermally Capillary column GC/MS No data 70-130 Pellizzari et al 1985b... 

Exhaled air (breath) Collection in Tedlar bag preconcentration by Tenax-GC thermal desorption HRGC/FID and HRGC/MS No data No data Krotoszynski et al. 1979... 

Alveolar air Collection of exhaled air using a specially-designed device to provide pure air for inhalation. Breath collected into duplicate evacuated canisters. GC/MS 0.5 pg/m (0.5 ppt, w/v) 112 (8% RSD) at 5.1 pg/m Raymer et al. 1990... 

Breath Collection using a spirometer adsorption on Tenax traps thermal desorption cap GC/MS No data No data Barkley et al. 1980... 

Breath Collection into canisters using spirometer cryofocussing thermal desorption cap. GC/MS-SIM low- g/m levels 49-80 Thomas et al. 1991... 

An issue of curiosity, engendering some little debate, is whether dogs do this with their exhaled breath before each inhaled breath collects samples for the aroma being sought. 

Expired air Breath collected in Teflon GC/MS No data No data Krotoszynski and Not... 

Breath Collection on Tenax GC thermal desorption HRGC/MS (IARC Method 5) 3 ppt 70-130 estimated Pellizzari et al. 1988... 

Breath Collection in sampling tube direct injection of sample GC/FID 100 ppb 100 Sherwood and Carter 1970... 

Breath Collection on Tenax GC thermal desorption to on-column cryogenic trap HRGC/MS 1.6 ppb (5-L sample) 86-90 Wallace et al. 1986, 1985... 

Breath Collection in bags, adsorption on silica gel desorption to headspace vial analysis of headspace gases GC/MS-SIM 0.1 ppb NR Gruenke et al. 1986... 

Fig. 5.14. Breath collection chamber and air circulation system for measurement of exhaled volatile hydrocarbons (Lawrence and Cohen, 1984.)...

An apparatus suitable for human breath collection was described by Lemoyne et al. (1987). Subjects were allowed to breathe for 4 min through a mouth piece connected to a Rudolph Valve from a Tedlar bag (Analygas Systems Ltd., Scarborough, Ontario, Canada) containing hydrocarbon-free air. Atmospheric air was hushed from the lungs and an aliquot of exhaled air collected during the succeeding 2 min while the hydrocarbon-free air was inspired. Hydrocarbons were concentrated by a loop-concentrator similar to that previously described and then injected into the GLC. 

The study shown in Figure 3.3 addresses the biochemical mechanism of lactose intolerance and uses the technique of breath collection and H2 analysis. Breath Hj rose after a lactose-intolerant child consumed a dose of lactose, but did not rise after a dose of equal weights of glucose and galactose. These results are consistent with the fact that lactose intolerance arises from a deficiency in lactase. 

Breath Collecting Apparatns Gas chromatography GC linked with mass spectrometry Partial Least Sqnares... 

Mixed-exhaled air. This technique involves the collection of the entire volume of exhaled air. It corresponds to a mixture of the alveolar air with air from the dead space. The collection apparatus may also contribute to the dead space. Total dead space should be considered and the concentration adjusted, either by subtraction, or by regression against some other technique unaffected by the dead space. Timing of the breath collection is important here since the concentration of the air in the dead space may equal that of the air in the workroom if the sample is taken during exposure, or it may equal zero if taken after the end of exposure. 

The practice of breath collection onto silica adsorbent for later analysis to compare to the results of an evidential breath-testing device (EBT) is currently being performed in some laboratories in the United States. The contents are emptied into a vial, diluted with an aqueous internal standard solution (n-propanol) and analyzed by headspace GC using procedures similar to those for blood alcohol analysis, but adjusted for sensitivity differences. Reanalysis of breath samples collected in this manner is not recommended, however, due to factors other than instrument performance, such as sample collection and operator errors. 

At the time of writing, no standard procedure has been adopted. In the next few sections, we discuss possible breath collection procedures, both for online and offline sampling. 

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