Determination of natural and synthetic colorants in prescreened dairy samples using liquid chromatography-diode array detection.
A simple and novel screening method for food colorants was proposed. Synthetic or natural colorants were discriminated as they were selectively adsorbed on cotton or RP-C18 sorbent columns, respectively. After elution, each fraction was monitored at 400, 530, and 610 nm for yellow, red, and green-blue-brown additives, respectively, with a DAD spectrophotometer. The screening method serves as a filter to indicate whether the target colorants are present above or below the detection limit of the method (6-15 or 25-10,000 n/mL for synthetic or natural colorants, respectively). Positive samples were discriminated by LC-DAD, using a flow system similar to that of the screening method. The LC-DAD discrimination/confirmation method is very sensitive; it exhibits a linear range of 0.01-50 microg/mL (excluding curcumin and caramel, which are linear up to 200 and 1,500 microg/mL, respectively). The method was applied to the determination of natural and synthetic colorants in dairy samples with good precision.
González
Mónica
M
Department of Analytical Chemistry, Campus de Rabanales, University of Córdoba, E-14071 Cordoba, Spain.
Gallego
Mercedes
M
Valcárcel
Miguel
M
D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods; D003611:Dairy Products / Q000032:analysis*; D005505:Food Coloring Agents / Q000032:analysis*; D011048:Polarography
D005505:Food Coloring Agents