Analytical performance criteria. Field evaluation of diacetyl sampling and analytical methods.
Ashley-K; McKernan-LT; Burroughs-E; Deddens-J; Pendergrass-S; Streicher-RP
J Occup Environ Hyg 2008 Nov; 5(11):D111-D116
Diacetyl and acetoin are ketones that are used extensively in the flavoring and food production industries. Both compounds are monitored in the workplace to assess exposures, to aid in the selection of respirators, and to evaluate the effectiveness of ventilation and other control procedures. Researchers from the National Institute for Occupational Safety and Health (NIOSH) published methods to sample and analyze airborne concentrations of diacetyl and acetoin in workplaces.(1) Recent laboratory investigations indicate that the diacetyl method is affected by humidity, resulting in an underestimation of true diacetyl concentration.(2) The effects of humidity on the collection and subsequent desorption of organic compounds on solid sorbent media has been investigated previously. McCammon and Woebkenberg(3) describe the effects of humidity on both silica gel and carbon molecular sieve. The polar nature of silica gel causes it to both adsorb water vapor and show a decrease in breakthrough capacity for non-water-soluble substances with increasing humidity. Carbon molecular sieves retain adsorbed species according to molecular size, and small organic compounds with molecular size similar towater must compete for sorption sites in an equilibrium at least partially based on concentration, which favors adsorption of water. In a study more specific to this effect, Karbiwnyk et al.(4) found that water vapor can interfere significantly in the measurement of volatile organic compounds using solid sorbents of varying hydrophobic characteristics. That interference is attributed to a reduction in retention of analyte during sampling.
Analytical-methods; Analytical-chemistry; Sampling; Sampling-equipment; Sampling-methods; Performance-capability; Equipment-reliability; Ketones; Testing-equipment; Exposure-assessment; Airborne-particles; Laboratory-testing; Humidity; Quality-control; Measurement-equipment; Vapors; Volatiles; Organic-compounds; Hydrophobic-bonds
Journal of Occupational and Environmental Hygiene