Performance of Laboratories Undertaking the Determination of Benzene in Air, as Codified in EPA Method TO-17: Results from the International AIR Proficiency Testing Scheme

Oral Presentation

Prepared by O. Butler1, I. Pengelly2, M. Whetton3, H. Finch4
1 - Health and Safety Laboratory , Harpur Hill , Buxton, Derbyshire, SK17 9JN, United Kingdom
2 - Health and Safety Laboratory , Harpur Hill , Buxton, Derbyshire, SK17 9JN,
3 - LGC Standards Proficiency Testing, 1 Chamberhall Business Park, Chamberhall Green, Bury, BL9 0AP, United Kingdom
4 - LGC Standards Proficiency Testing, 1 Chamberhall Business Park, Chamberhall, Bury, BL9 0AP, United Kingdom


Contact Information: owen.butler@hsl.gsi.gov.uk; 129-821-8560


ABSTRACT

Sampling of volatile organic compounds (VOCs) in air onto sorbent tubes with subsequent laboratory analysis using thermal desorption gas chromatographic techniques is well-established and is increasingly being used in the United States as an alternative to canister sampling. This methodology is codified in a number of standard methods such as EPA TO-17, ISO 16000-6, ISO 16017-1 and 16017-2 that employ either pumped or diffusive sampling strategies. The AIR proficiency PT scheme is an international proficiency testing (PT) scheme designed the evaluate the performance of laboratories that undertake chemical pollutants in air testing and is administered by LGC Standards PT in partnership with the Health and Safety Laboratory.

The aims of this presentation are

• To describe how sorbent tube PT samples are prepared. The approach used, based upon procedures codified in ISO 6145-4, involves the sampling of a set volume of VOC enriched air onto individual sorbent tubes using an automated loading rig. This approach mimics real air sampling and is highly precise.
• To summarize the PT performance of laboratories who partake in the “Tenax sorbent spiked at ambient air concentrations” sample type. As an example, benzene data, for sorbent tubes spiked in the range 50 – 300 ng, will be presented from the most recent 10 PT rounds. Currently 10 US and Canadian laboratories participate alongside their peers from 40 other international laboratories.
• To interpret this PT performance in light of codified measurement quality objectives set out in the US (EPA NATTS QA objectives) and in the European Union (Air Quality Directive 2008/50/EC).