title: In situ derivatisation and extraction of volatile fatty acids entrapped on anion-exchange resin from aqueous solutions and urine as a test matrix using pentafluorobenzyl bromide in supercritical carbon dioxide.
abstract: The simultaneous extraction and derivatisation of anion-exchange resin-trapped volatile fatty acids (C2-C5) as their pentafluorobenzyl esters has successfully been performed under CO2 supercritical fluid extraction conditions. Volatile fatty acid standards of acetic, propionic and n-butyric acids (at 20 and 100 ppm) as their ester derivatives were recovered at 78.0-101.5% (C.V. 3.5-7.5%, n=6 and 7). Likewise, acrylic acid recoveries were 57.0-61.0% (C.V. 5.5-5.6%, n=6 and 7). This methodology was applied to the quantitation of acetic, propionic, n-butyric and n-valeric acids in spiked urine as a test matrix. Initial clean-up of phosphate and sulfate in the urine was required prior to anion-exchange application and this was achieved by barium salt precipitation. Recoveries ranged from 36 to 66.5% (C.V. 5.9-14.4%, n=9 and 6).
authors.affiliation: Australian Government Analytical Laboratories, Kingston, Tasmania.
authors.forename: M T
authors.initials: MT
authors.lastname: Cummins
authors.forename: R J
authors.initials: RJ
authors.lastname: Wells
mesh_terms: D000837:Anion Exchange Resins; D002245:Carbon Dioxide; D005232:Fatty Acids, Volatile / Q000737:chemistry / Q000302:isolation & purification* / Q000652:urine; D005464:Fluorobenzenes / Q000097:blood*; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008297:Male; D012996:Solutions; D005466:Fluorocarbons
chemical_list: D000837:Anion Exchange Resins; D002245:Carbon Dioxide; D005232:Fatty Acids, Volatile; D005464:Fluorobenzenes; D012996:Solutions; C025063:pentafluorobenzyl bromide; D005466:Fluorocarbons