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Validation of a passive sampler for valeraldehyde.

Tasi-S; Que Hee-S
American Industrial Hygiene Conference and Exposition, May 19-23, 1997, Dallas, Texas. Fairfax, VA: American Industrial Hygiene Association, 1997 May; :45-46
O-(2,3,4.5,6·pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) has been used to analyze aldehydes in water because of its fast quantitative reaction to form oximes suitable for sensitive detection at the picogram (pg) level by gas chromatography/mass spectrometry (GC/MS) and gas chromatography/ electron capture detection (GC/ECD). The PFBHA method also has been used to analyze aldehydes in air samples by dynamic sampling. The aim of this research was to validate a new valeraldehyde passive sampler for personal sampling in the environmental / industrial hygiene field. Effects of different temperatures, humidities, and face velocities were evaluated. Sampling capacity, shelf life. and storage stability of the sampler were determined. A 13-mm diameter and 0.2-cm thick pellet of PFBHA coated Tenax GC (10%, w/w) was made by a hand press. The sampler has a silicone membrane on top and a diffusion path length of 1.1 cm and is contained in a lapel clip-holder. The sampling constant was determined by exposures at known face velocities (20 to 70 fpm.) Valeraldehyde vapors were generated by using a syringe pump at a constant injection rate to introduce liquid aldehyde into pure air of known flow rate that was diluted appropriately before delivery into the exposure chamber. The ppm-hour levels were equivalent to 0.25, 0.5, 1, 1.5, and 2 times the PEL for 8 hours. Desired humidities (3 +/-1%, 36 +/-2% and 79 + / -2%) were generated by vaporizing specific volumes of water into the system by another syringe pump. An ice bath and heating oven were used to obtain the cold and hot exposure environments (9 +/-1 degree C, 25 +/-1 degree C, and 48 +/-2 degrees C) The PFBHA-valeraldehyde oxime was desorbed by hexane, analyzed by GC/ MS, and determined by selected ion monitoring at m/ z 181. The desorption efficiency was found to be 96.5 +/-5.4%. The shelf life of the sampler was longer than 3 months, and the sample stability was longer than 6 weeks with no difference between room storage and 4 degrees C storage. The capacity was 2.83 +/-0.30 mg (using vapor spiking.) There were no significant effects from different relative humidities, exposure temperatures, and intermittent sampling. The experimental sampling rate of this sampler for valeraldehyde vapor was 4.52 + / - 0.14 mL/min (from 8 degrees C to 50 degrees C.) The mass collected was independent of face velocities in the range of 20 to 70 fpm.
Air-monitoring; Air-samplers; Air-sampling; Air-sampling-equipment; Air-sampling-techniques; Chromatographic-analysis; Environmental-exposure; Laboratory-techniques; Laboratory-testing; Membrane-filters; Quantitative-analysis; Sampling; Sampling-methods; Spectrographic-analysis; Vapors
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Research Tools and Approaches: Exposure Assessment Methods
Source Name
American Industrial Hygiene Conference and Exposition, May 19-23, 1997, Dallas, Texas
Performing Organization
University of California Los Angeles, Los Angeles, CA