title: Surfactant to dye binding degree based approach for the selective determination of L-glutamate in foodstuffs.
abstract: A selective method for the determination of L-glutamate in foodstuffs has been developed. It was based on the competition established between the analyte and the dye Coomassie brilliant blue G (CBBG) to interact with the surfactant didodecyldimethylammonium bromide (DDABr). The measurement parameter was the amount of DDABr required to reach a given dye-to-surfactant binding degree. It was obtained by photometric titration on the basis of the changes observed in the spectral characteristics of the dye when CBBG-DDABr aggregates were formed. The calibration graph obtained was linear in the L-glutamate concentration interval 0.2-5 mM (detection limit 0.05 mM). The high selectivity of the proposed method (other amino acids and food additives did not interfere at the concentrations present in foodstuffs) permitted the direct analysis of food samples after dissolution of the analyte in hot water. The accuracy of the surfactant to the dye binding degree method was demonstrated by determining L-glutamate in different kinds of foodstuffs (liquid and dried soups, seasonings, pasta sauces and dried mushroom creams) and comparing the results obtained with those provided by the commercial Boehringer Mannheim essay.
authors.affiliation: Department of Analytical Chemistry, Faculty of Sciences, University of Córdoba, Edificio Anexo Marie Curie, Campus de Rabanales, 14071, Córdoba, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Pedraza
authors.forename: María Dolores
authors.initials: MD
authors.lastname: Sicilia
authors.forename: Soledad
authors.initials: S
authors.lastname: Rubio
authors.forename: Dolores
authors.initials: D
authors.lastname: Pérez-Bendito
mesh_terms: D002138:Calibration; D005504:Food Analysis / Q000379:methods* / Q000592:standards; D018698:Glutamic Acid / Q000032:analysis* / Q000737:chemistry; D007202:Indicators and Reagents; D011786:Quality Control; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000378:metabolism*; D012394:Rosaniline Dyes / Q000737:chemistry / Q000378:metabolism*; D013501:Surface-Active Agents / Q000737:chemistry / Q000378:metabolism
chemical_list: D007202:Indicators and Reagents; D000644:Quaternary Ammonium Compounds; D012394:Rosaniline Dyes; D013501:Surface-Active Agents; C046112:didodecyldimethylammonium; D018698:Glutamic Acid; C004692:coomassie Brilliant Blue