title: UV-visible-DAD and 1H-NMR spectroscopy data fusion for studying the photodegradation process of azo-dyes using MCR-ALS.
abstract: The photodegradation process of three azo-dyes - Acid Orange 61, Acid Red 97 and Acid Brown 425 - was monitored simultaneously by ultraviolet-visible spectroscopy with diode array detector (UV-vis-DAD) and (1)H-nuclear magnetic resonance ((1)H-NMR). Multivariate curve resolution-alternating least squares (MCR-ALS) was applied to obtain the concentration and spectral profile of the chemical compounds involved in the process. The analysis of the H-NMR data suggests there are more intermediate compounds than those obtained with the UV-vis-DAD data. The fusion of UV-vis-DAD and the (1)H-NMR signal before the multivariate analysis provides better results than when only one of the two detector signals was used. It was concluded that three degradation products were present in the medium when the three azo-dyes had practically degraded. This study is the first application of UV-vis-DAD and (1)H-NMR spectroscopy data fusion in this field and illustrates its potential as a quick method for evaluating the evolution of the azo-dye photodegradation process.
authors.affiliation: Department of Analytical and Organic Chemistry, Rovira i Virgili University, C/Marcel·lí Domingo, s/n, Campus Sescelades, E-43007 Tarragona, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Fernández
authors.forename: M
authors.initials: M
authors.lastname: Pilar Callao
authors.forename: M Soledad
authors.initials: MS
authors.lastname: Larrechi
mesh_terms: D001391:Azo Compounds / Q000032:analysis* / Q000737:chemistry; D004396:Coloring Agents / Q000032:analysis* / Q000737:chemistry; D006801:Humans; D007700:Kinetics; D016018:Least-Squares Analysis; D015999:Multivariate Analysis; D019906:Nuclear Magnetic Resonance, Biomolecular; D010782:Photolysis; D013056:Spectrophotometry, Ultraviolet / Q000706:statistics & numerical data; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D014874:Water Pollutants, Chemical; D014867:Water; C549763:acid red 97
keywords: Azo-dyes; Data fusion; Photodegradation process; Proton-nuclear magnetic resonance spectroscopy; UV–visible spectroscopy