Personal Passive Sampling Method for Nitrous Oxide in Air
Abstract No:
1377
Abstract Type:
Professional Poster
Authors:
J Soo1
Institutions:
1NIOSH, Morgantown, WV
Presenter:
Jhy-Charm Soo, Ph.D.
NIOSH
NIOSH
Description:
Dental workers may develop short-term behavioral and long-term reproductive health effects caused by exposure to waste nitrous oxide (N2O).
Situation / Problem:
The current compliance sampling method specifies collection by diffusion badge packed with molecular sieve 5Å adsorbent. However, the adsorbent is hydrophilic and prone to back diffusion during passive sampling. This study aims to establish a new sampling and analytical method using Thermal Desorption-Gas Chromatography- Mass Spectrometry (TD-GC-MS).
Methods:
A barium exchanged Zeolite Socony Mobil–5 (Ba-ZSM5) was chosen as an adsorbent and packed into an industry standard TD tube. A dynamic atmosphere generation system produced a range of concentration levels of N2O (12.5 to 50 ppm; 0.5-2 times NIOSH REL) in air at various relative humidities (RH; 3, 20, and 80%) at 24˚C. Six replicate TD samples in parallel under each humidity condition (n=3) were passively collected for up to six-hour periods along with reference samples (molecular sieve 5Å) from each trial. All analytical work was performed on an Agilent GC coupled with MS. A Restek Rt-Msieve 5A PLOT GC column was chosen which eliminated coelution of N2O and CO2. A test chamber's uniformity was confirmed by computational fluid dynamics (CFD) simulation. The effects of time dependency, humidity, and back diffusion were determined.
Results / Conclusions:
The face velocity around the sampling ports inside the test chamber was in good agreement with the typical workplace environment (< 0.3 m/sec). The retention time of N2O is 8.7 minutes whereas CO2 elutes at 11-13 minutes. The reported N2O limit of detection and limit of quantification were 0.054 µg and 0.180 µg, respectively. Linearity was observed in amount of N2O as sampling time increased. No humidity effect on N2O adsorption was observed at a sampling time ≤ 2 hours. No back diffusion effect was seen when TD samples were exposed to humid air.
Primary Topic:
Sampling and Analysis
Secondary Topics:
Healthcare
Sampling and Analysis
Co-Authors
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1 Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia, USA.2 School of Dentistry, West Virginia University, Morgantown, West Virginia, USA.