title: Evaluation of complex spectral-pH three-way arrays by modified bilinear least-squares: determination of four different dyes in interfering systems.
abstract: This article reports on the first application of a modified version of the bilinear least-squares model to absorbance-pH second-order data recorded for complex samples. The latter are composed of fruit drink powders, where four different analytes and additional background components occur. The analytes are the common juice colorants tartrazine, yellow sunset, allura red and indigo carmine. The data have been measured after generating a double pH gradient within a flow injection system. The selected chemometric methodology adequately exploits the second-order advantage, needed to take into account the background interferents present in real samples. Due to severe spectral overlapping between the acid and basic forms of each of the colorants in the working pH range, other second-order multivariate calibration methods such as parallel factor analysis and multivariate curve resolution-alternating least-squares could not be successfully applied to the presently studied samples. Recoveries of 94.8, 104.7, 109.3 and 105.3% were obtained for yellow sunset, indigo carmine, allura red and tartrazine respectively in the real test samples.
authors.affiliation: Cátedra de Química Analítica, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ciudad Universitaria, Santa Fe (S3000ZAA) CC. 242, Argentina.
authors.forename: Nilda R
authors.initials: NR
authors.lastname: Marsili
authors.forename: Adriana
authors.initials: A
authors.lastname: Lista
authors.forename: Beatriz S Fernandez
authors.initials: BS
authors.lastname: Band
authors.forename: Héctor C
authors.initials: HC
authors.lastname: Goicoechea
authors.forename: Alejandro C
authors.initials: AC
authors.lastname: Olivieri
mesh_terms: D001391:Azo Compounds / Q000032:analysis; D001628:Beverages / Q000032:analysis*; D002138:Calibration; D017022:Flow Injection Analysis; D005505:Food Coloring Agents / Q000032:analysis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007203:Indigo Carmine / Q000032:analysis; D016018:Least-Squares Analysis; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000379:methods*; D013645:Tartrazine / Q000032:analysis
chemical_list: D001391:Azo Compounds; D005505:Food Coloring Agents; C005915:Allura Red AC Dye; D007203:Indigo Carmine; C005842:6-hydroxy-5-((p- sulfophenyl)azo)-2-naphthalenesulfonic acid disodium salt; D013645:Tartrazine