Second order advantage in the determination of amaranth, sunset yellow FCF and tartrazine by UV-vis and multivariate curve resolution-alternating least squares.
A direct spectrophotometric method for the determination of three artificial colors--amaranth, sunset yellow FCF and tartrazine--in beverages samples is proposed. The spectra were recorded between 359 and 600 nm. The spectra of the samples (just filtrated), pure dyes (concentrations ranged between 0.01 and 1.8 mg L(-1) for amaranth, 0.08 and 4.4 mg L(-1) for sunset yellow and 0.04 and 1.8 mg L(-1) for tartrazine) and synthetic mixtures were disposed in a column-wise augmented data matrix. This kind of data structure, analyzed by multivariate curve resolution-alternating least squares (MCR-ALS) makes it possible to exploit the so called 'second order advantage'. MCR-ALS algorithm was applied to the experimental data under the non-negativity and equality constraints. As a result, the concentration of each dye in the samples and their corresponding pure spectra were obtained. The results were validated using internal reference materials and no significant differences were found (alpha=5%) between the reference values and the ones obtained with the proposed method. The second order advantage made it possible to obtain unbiased results even in the presence of interferences.
Llamas
Natalia Elizabeth
NE
FIA Laboratory, Department of Chemistry, Universidad Nacional del Sur, INQUISUR (UNS-CONICET), Av. Alem 1253, (B8000CPB), Bahía Blanca, Buenos Aires, Argentina.
Garrido
Mariano
M
Di Nezio
María Susana
MS
Fernández Band
Beatriz Susana
BS