title: Differential pulse polarographic determination of alpha-dicarbonyl compounds in foodstuffs after derivatization with o-phenylenediamine.
abstract: A differential pulse polarographic method has been developed for the indirect determination of diacetyl and other vicinal diketones in foodstuffs, based on the quantitative derivatization of the diketones with o-phenylenediamine to give quinoxalines. The method allows the identification of diacetyl and methylglyoxal in brandy, vinegar, wine, and butter samples. The polarographic reduction peaks of the quinoxalines formed are sufficiently separate, in some cases, to allow the simultaneous determination of these two compounds. The polarographic method is not affected by the presence of sulfite ion, probably because the o-phenylenediamine is capable of dislodging the alpha-diketones from their sulfite complexes.
authors.affiliation: Centro de Investigação em Química da Universidade do Porto, Departamento de Química da Faculdade de Ciências, Porto, Portugal. jarodrig@fc.up.pt
authors.forename: J A
authors.initials: JA
authors.lastname: Rodrigues
authors.forename: A A
authors.initials: AA
authors.lastname: Barros
authors.forename: P G
authors.initials: PG
authors.lastname: Rodrigues
mesh_terms: D019342:Acetic Acid / Q000032:analysis; D000434:Alcoholic Beverages / Q000032:analysis; D002079:Butter / Q000032:analysis; D005504:Food Analysis / Q000379:methods*; D007202:Indicators and Reagents; D007659:Ketones / Q000032:analysis*; D010655:Phenylenediamines; D011048:Polarography / Q000379:methods; D014920:Wine / Q000032:analysis
chemical_list: D007202:Indicators and Reagents; D007659:Ketones; D010655:Phenylenediamines; D002079:Butter; C034193:1,2-diaminobenzene; D019342:Acetic Acid