Development and validation of a canister method for measuring ethylene oxide in ambient air.
A sampling and analytical method for measuring ethylene oxide (EO) in ambient air was developed and evaluated. The method is based on the use of evacuated canisters and gas chromatography-mass spectrometry (GC-MS). The objectives of this work were to characterize the performance of the method with respect to the following: (1) stability/recovery of ethylene oxide in a canister over a 15-day holding time; (2) detection capability; and (3) measurement of EO in an ambient air matrix. Both electropolished and silica-lined stainless steel canisters were evaluated in this study. The method evaluation involved both laboratory and field tests. The recovery of the EO was evaluated both on an absolute basis and relative to a spiked internal standard of toluene. EO spiked at levels of 2 ppbv and 20 ppbv was found to be stable for holding times of up to 15 days at 25 degrees C in both a humidified nitrogen matrix and in ambient air. The detection limit of the method was found to be 0.25 ppbv using EPA's traditional approach of seven replicate analyses of a low-level standard and 0.20 ppbv using a probability-based approach. EO recoveries in the laboratory stability study generally were 100 +/- 25%, and did not vary by canister type, nor did the EO recoveries decrease with holding time. Field studies demonstrated that the method is capable of detecting EO (as well as benzene and toluene) in an ambient air matrix.
Eklund
Bart M
BM
URS, P.O. Box 201088, Austin, Texas 78720-1088, USA. bart_eklund@urscorp.com
Williams
C Herndon
CH
Bontempo
L Wade
LW
Isbell
Molly
M
Loos
Karl R
KR
D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D005027:Ethylene Oxide / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry; D015203:Reproducibility of Results
D000393:Air Pollutants; D005027:Ethylene Oxide