RR1138 - Validation of a measurement method for diacetyl using sorbent tubes and thermal desorption
Diacetyl, also known as 2,3-butanedione, and the closely related chemical 2,3-pentanedione, are naturally occurring substances with a characteristic butter-like odour found in foods such as dairy products, beer and fruits. Diacetyl is also added to various food products as artificial butter flavouring and both substances are present in emissions generated by coffee roasting and grinding. Occupational levels of diacetyl exposure has been linked with the lung disease bronchiolitis obliterans which is life threatening and irreversible. In Great Britain, occupational exposure limits to protect workers' health are based on recommendations from SCOEL (the European Commission Scientific Committee on Occupational Exposure Limits). SCOEL has recommended introducing an 8-hour time weighted average occupational exposure limit for diacetyl of 20 ppb and a short term exposure limit (STEL) of 100 ppb. Existing scientific measurement methods lack the necessary sensitivity to measure these levels of exposure.
This report describes a new sensitive method for measurement of diacetyl based on the use of thermal desorption tubes for sampling and gas chromatography-mass spectrometry for analysis. The samplers may be used in either pumped (active) or diffusive (passive) mode. For measurement of short duration peak concentrations, or determining compliance with the STEL, pumped sampling is most effective. For longer sampling periods, in particular whole shift monitoring, diffusive sampling is preferable. This method is also applicable to 2,3-pentanedione.
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