Synthesis of aldehyde oxime standards.
American Industrial Hygiene Conference and Exposition, May 19-23, 1997, Dallas, Texas. Fairfax, VA: American Industrial Hygiene Association, 1997 May; :51-52
Carbonyl compounds (especially those that are low molecular weight aldehydes) are receiving increasing attention in workplace air exposures, indoor air quality, and as disinfection byproducts in drinking water. Formaldehyde, acetaldehyde, and crotonaldehyde are known animal carcinogens. There is need to have a method that can be utilized for both water and air samples at ppb-ppm concentrations. While 2,4-dinitrophenylhydrazine is presently the only method used in this manner, other methods need to be developed because of difficulties with this method. The reagent O-(2,3,4,5,6-pentafluorophenyl)methyIhydroxylamine hydrochloride (PFBHA) is the most promising alternative reagent. Unfortunately, there are no commercial standards for the oxime derivatives of the carbonyl compounds. The conditions to produce pure oxime standards at yields >80% have been optimized for a number of low molecular weight aldehydes relative to temperature, reaction time, and isolation procedures. The optimum synthesis procedure differs for different aldehydes. About 1.1 to 1.3 times PFBHA is usually necessary, and heating by turntable microwaving at 87 degrees C is important for three heating-cooling cycles. Cooling at room temperatures is more efficient than ice water quenching. Three extractions with hexane are optimal except for formaldehyde oxime, which requires precipitation and centrifugation. Quantitative analyses for purity and yield were done by gas chromatography/electron capture detection and gas chromatography/mass spectrometry, using nonpolar capillary gas chromatographic columns.
Air-filters; Air-monitoring; Air-samplers; Air-sampling; Air-sampling-equipment; Air-sampling-techniques; Air-treatment; Carcinogenicity; Carcinogens; Chemical-hypersensitivity; Chromatographic-analysis; Exposure-assessment; Exposure-levels; Filter-materials; Filter-membranes; Gas-chromatography; Laboratory-techniques; Laboratory-testing; Mathematical-models; Membrane-filters; Quality-control; Quantitative-analysis; Sampling; Sampling-methods; Spectrographic-analysis; Water-analysis; Water-industry
Research Tools and Approaches: Exposure Assessment Methods
American Industrial Hygiene Conference and Exposition, May 19-23, 1997, Dallas, Texas
University of California Los Angeles, Los Angeles, CA