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

Creation of 0.10-cm-1resolution quantitative infrared spectral libraries for gas samples

“…Details related to gravimetric standards preparation have been discussed previously, but will be briefly described below. [11][12][13] For liquid samples, an evacuated cylinder is weighed to an accuracy of 0.1 g on a top loading balance with a capacity of 32 kg. The cylinder is fitted with a CGA-350 adaptor that contains a septum and allows injection of the sample directly into the cylinder.…”

An Analytical Method to Determine Henry’s Law Constant For Selected Volatile Organic Compounds At Concentrations And Temperatures Corresponding To Tap Water Use

“…Air standards for low concentrations of specific VOC mixtures are not available from NBS 25 , and are difficult to prepare accurately. Exponential dilution flasks are not accurate at low VOC concentrations because some VOCs stick to the walls of the flasks.…”

Generation of sub-ppb level vapor phase mixtures of biogenic volatile organic compounds from liquid phase standards and stepwise characterization of their volatilization properties by thermal desorption–gas chromatography–mass spectrometry

“…For this purpose, the use of a gaseous standard is a common option, as it allows the elimination or suppression of major experimental drawbacks (e.g., the matrix effect) encountered due to the phase difference between the sample (gas) and the standard phases (liquid) [10,11]. However, the storage of diverse volatiles in gas phase may be complicated as sample integrity can degrade with time [12]. The stability of common storage media has been evaluated using diverse target volatiles, e.g., MTs in cylinders [13]; aldehydes and terpenes in canisters [14]; and alkanes, alkenes, aromatics, and BVOCs in both canisters and Tedlar bags [15].…”

“…standards prepared and stored in canisters were subject to significant losses over time due to physical adsorption or chemical reactions on the canister walls [14]. To overcome these limitations of storing gas-phase standards of volatile compounds, some researchers investigated their generation using liquid-phase standards [12,[16][17][18][19]. To this end, many authors introduced diverse methods (e.g., capillary diffusion) to convert the liquid phase chemicals into the gaseous standards [16,17,19].…”