title: Simultaneous spectrophotometric determination of tartrazine, patent blue V, and indigo carmine in commercial products by partial least squares and principal component regression methods.
abstract: Two multivariate calibration methods, partial least squares (PLS-1) and principal component regression (PCR) were proposed and successfully applied to the simultaneous determination of three dyes, tartrazine (T) (E-102), patent blue V (P) (E-131), and indigo carmine (I) (E-132) in mixtures by ultraviolet-visible absorption spectrophotometry. Calibration models were evaluated by internal validation (prediction of dyes concentration in its own designed training set of calibration), by cross-validation (obtaining statistical parameters that show the efficiency for a calibration fit model), and by external validation over 19 synthetic mixtures of the three dyes in different ratios containing 2.4-17.6 mg l(-1) of T, 1.6-5.6 mg l(-1) of P, and 3.2-17.5 mg/l(-1) of I, with recoveries between 93.5 and 103.1% and over three commercial products, in which the proposed calibration models were satisfactorily applied without separation step. Repeatability and reproducibility studies (with the Students's and F tests) were achieved over two series of nine standards for each dye, showing no significant differences at 95% confidence level.
authors.affiliation: Department of Analytical Chemistry and Food Technology, University of Castilla-La Mancha. 13071 Ciudad Real, Spain.
authors.forename: J J
authors.initials: JJ
authors.lastname: Nevado
authors.forename: J R
authors.initials: JR
authors.lastname: Flores
authors.forename: M J
authors.initials: MJ
authors.lastname: Llerena
authors.forename: N R
authors.initials: NR
authors.lastname: Fariñas