title: Optimizing the separation of food dyes by capillary electrophoresis.
abstract: In this work, the separation of eleven food dyes was evaluated by MEKC in electrolytes composed of tetraborate (TBS), Brij 35, and acetonitrile (ACN) using a factorial design at the following levels: TBS concentration (5 and 10 mmol L(-1)), pH (9.5 and 10.1), Brij concentration (5 and 20 mmol L(-1)), and ACN (5 and 15%). Several response functions were evaluated and indicated 10 mmol L(-1) TBS (pH 10.1), 15% ACN, and 20 mmol L(-1) Brij 35 as best values. However, baseline resolution was not achieved (R(cp) = 0.76) and the method lacked robustness. New conditions were sought by studying the dye mobility versus Brij concentration (5-20 mmol L(-1)). A set of well resolved and more uniformly spaced peaks was obtained with an electrolyte consisting of 7.5 mmol L(-1) TBS (pH 10.1), 10 mmol L(-1) Brij, and 15% ACN. Under these new conditions, complete resolution of the 11 dyes was achieved in less than 9 min. Migration time and peak area repeatabilities were better than 1.6% and 5% CV and the LODs were 0.47 to 2.3 microg mL(-1). The methodology was applied to fruit juice powders, lollipops, and other hard and soft chewable treats.
authors: Institute of Chemistry, University of Sao Paulo, C.P. 26077, 05513-970, Sao Paulo, SP, Brazil.
authors: Alessandra Vincenzi
authors: AV
authors: Jager
authors: Fernando Gustavo
authors: FG
authors: Tonin
authors: Marina Franco Maggi
authors: MF
authors: Tavares
mesh_terms: D004396:Coloring Agents / Q000302:isolation & purification*; D019075:Electrophoresis, Capillary / Q000379:methods* / Q000592:standards; D005503:Food Additives / Q000302:isolation & purification*; D005504:Food Analysis / Q000592:standards*; D015203:Reproducibility of Results
chemical_list: D004396:Coloring Agents; D005503:Food Additives