Trace analysis of organic pollutants in air by polymer adsorption and dual flame ionization detection—electron-capture detection capillary gas chromatography

Preparation of accurate multicomponent gas standards of volatile toxic organic compounds in the low-parts-per-billion range

“…In addition, two of the compounds, 1,3-butadiene and ethylene oxide, are gases at room temperature and had to be chilled to their liquid state for preparation. Analytical results for a typical group 4 mixture are shown in Table VIII. Analyses of a number of these standards indicated that ethylene oxide exhibited instability.…”

“…Disk-shaped electrodes of micrometer dimensions allow fast voltammetric measurements because of the reduced ohmic * Author to whom correspondence should be addressed. drop and cell time constant associated with these electrodes (1)(2)(3)(4)(5). Such measurements are useful to determine the rates of rapid processes associated with heterogeneous electron transfer (3-8).…”

“…Recent analytical research has focused on techniques for the preconcentration of air samples containing parts-perbillion levels of volatile organics by using sorbents or cryogenic temperatures. Analyses of the enriched organics have generally been conducted by capillary column gas chromatography coupled to flame-ionization and electron-capture detectors (4) or a mass spectrometer (5, 6).…”

Multipoint calibration of a gas chromatograph using cryogenic preconcentration of a single gas standard containing volatile organic compounds

“…Once the system was set up, experiments were performed to determine: (1) if there were any sorption/desorption effects within the sampling system, (2) the reproducibility (analytical precision) of replicate injections of a single sample, (3) the effect on the trapping efficiency by precooling the traps or no precooling before flowing sample through them, (4) the trapping efficiencies of different trapping times and the same flow rate, and (5) the effect on the trapping efficiency using different flow rates.…”

“…In the past, analytical techniques involving sorbents or cryogenic temperature have been used to preconcentrate air samples and cylinder-contained gas standards containing parts-per-billion levels of volatile organic compounds. These enriched samples have been analyzed by capillary column GC-ECD and GC-FID (4,5) or mass spectrometry (GC-MS) (6,7). Others have used a method involving the use of an automated cryogenic system to determine volatile organic compounds in air by pulling the sample, contained in polymeric bags, canisters, or on solid adsorbents, through a trap immersed in a cryogenic fluid such as liquid nitrogen (8).…”