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Synthesis of the O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine oximes of selected carbonyl compounds and their determination by liquid chromatography with ultraviolet detection.

Authors
Wiesenthal-K; Jehlar-A; Que-Hee-SS
Source
J AOAC Int 2000 Jul; 83(4):859-869
NIOSHTIC No.
20029976
Abstract
The aims were to develop a liquid chromatographic (LC) method with ultraviolet detection (UVD) for O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) O-oximes of common aldehydes and ketones, and to define the steric limits of the synthetic reaction used to make the PFBHA O-oxime standards for gas chromatographic (GC) and LC methods. Ten new O-oximes were synthesized with the new optimized method, and their purities were demonstrated by GC/electron-capture detection (ECD), GC/mass spectrometry (MS), ultraviolet spectroscopy, infrared spectroscopy, and proton and 13C-nuclear magnetic resonance spectroscopy. Ketones substituted at both beta-carbons relative to the carbonyl carbon, like diisobutyl ketone and 2,4-hexanedione, showed lower synthetic yields by wet chemistry methods. A new C18 reverse-phase LC method with UVD at 200 nm and acetonitrile-water in both the isocratic and gradient-elution modes was then developed to sensitively resolve a mixture of 13 pure PFBHA O-oximes. The detection limit was near 100 ng O-oxime/mL or about 14-50 ng aldehyde/mL and the least quantifiable limits were near 500 ng/mL or about 70-250 ng aldehyde/mL, with lower limits for glyoxal, methylglyoxal, benzaldehyde, and acetophenone. Carbonyl compounds in 500 mL water samples were then determined in distilled water and tap water by gradient elution. Vapors of n-valeraldehyde and acrolein generated in gas bags at concentrations near occupational guidelines were also sampled, desorbed, and then determined by either isocratic or gradient elution at 200 or 254 nm within 30-45 min.
Keywords
Chemical-synthesis; Chromatographic-analysis; Ultraviolet-light; Ultraviolet-spectrometry; Aldehydes; Gas-chromatography; Ketones; Carbonyls
Contact
Department of Environmental Health Sciences and UCLA Center for Occupational and Environmental Health, Los Angeles, CA 90095-1772
CODEN
JAINEE
Publication Date
20000701
Document Type
Journal Article
Funding Amount
515055
Funding Type
Grant
Fiscal Year
2000
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-003120
Issue of Publication
4
ISSN
1060-3271
Priority Area
Research Tools and Approaches: Exposure Assessment Methods
Source Name
Journal of AOAC International
State
CA
Performing Organization
University of California Los Angeles, Los Angeles, CA
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