title: Trace-level screening of dichlorophenols in processed dairy milk by headspace gas chromatography.
abstract: A headspace gas chromatographic approach based on flame ionization detection has been successfully developed for the determination of parts-per-billion levels of 2,4-dichlorophenol and 2,6-dichlorophenol in processed dairy milk. Under the right environmental conditions, these compounds are produced as products of the reductive dechlorination of pentachlorophenol. Maintaining a highly inert chromatographic system and employing a recently commercialized inert capillary column permits the analysis of 2,4-dichlorophenol and 2,6-dichlorophenol without derivatization. Further, a detection limit improvement of more than a factor of two was achieved by adding sodium sulfate to substantially decrease the solute partition coefficient in the matrix. A detection limit of 1 ng/g and a limit of quantitation of 2 ng/g were attained, and complete analysis can be conducted in < 13 min. Reproducibility of area counts over a range from 20 to 200 ng/g and over a period of 2 days were found to be less than 6% (n = 20). A linear range from 5 to 500 ng/g with a correlation coefficient of at least 0.9992 was obtained for 2,4-dichlorophenol and 2,6-dichlorophenol. Spike recoveries from 10 to 500 ng/g for all the analytes range from 92 to 102%.
authors.affiliation: Department of Science, University of Alberta, Edmonton, Alberta.
authors.forename: Kaelyn
authors.initials: K
authors.lastname: Gras
authors.affiliation: Dow Chemical Canada ULC, Fort Saskatchewan, Alberta, Canada. luong@dow.com.|Australian Centre for Research on Separation Science (ACROSS), University of Tasmania, Hobart, Tasmania, Australia. luong@dow.com.
authors.forename: Jim
authors.initials: J
authors.lastname: Luong
authors.affiliation: Dow Chemical Canada ULC, Fort Saskatchewan, Alberta, Canada.|Australian Centre for Research on Separation Science (ACROSS), University of Tasmania, Hobart, Tasmania, Australia.|ARC Training Centre for Portable Analytical Separation Technologies (ASTech), University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: Ronda
authors.initials: R
authors.lastname: Gras
authors.affiliation: Australian Centre for Research on Separation Science (ACROSS), University of Tasmania, Hobart, Tasmania, Australia.|ARC Training Centre for Portable Analytical Separation Technologies (ASTech), University of Tasmania, Hobart, Tasmania, Australia.|Trajan Scientific and Medical, Victoria, Australia.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Shellie
mesh_terms: D000818:Animals; D002733:Chlorophenols / Q000032:analysis*; D002849:Chromatography, Gas; D008892:Milk / Q000737:chemistry*; D015203:Reproducibility of Results
chemical_list: D002733:Chlorophenols; C032729:2,6-dichlorophenol
keywords: Dichlorophenols; Headspace chromatography; Processed dairy milk