title: Determination of carmine food dye (E120) in foodstuffs by stripping voltammetry.
abstract: The behavior of the food colorant agent carmine (E120) was studied by square-wave adsorptive stripping voltammetry (SW-AdSV) at the hanging mercury drop electrode. It was observed that carmine gave a sensitive stripping voltammetric peak at -350 mV in pH 3 acetate buffer. The cyclic voltammetric technique was also used to characterize the electrochemical reduction process of carmine. The adsorptive voltammetric signal was evaluated with respect to various experimental conditions, and the optimized values were supporting electrolyte, acetate buffer; buffer acidity, pH 3; dye concentration, 3 x 10(-7) M; accumulation time, 150 s; accumulation potential, -0.2 V; scan rate, 300 mV/s; pulse amplitude, 185 mV; SW frequency, 20 Hz; working electrode area, 0.6 mm2; and convection rate, 2600 rpm. The SW-AdSV peak currents depended linearly on the concentration of carmine from 5 x 10(-8) to 1.25 x 10(-7) mol/L (r = 0.99). A detection limit of 1.43 x 10(-9) mol/L with an RSD of 2.2% and a mean recovery of 97.9% were obtained. Possible interferences by several substances usually present in food products such as food additive dyes (E102, E100, E123, E127, and E129), artificial sweeteners, preservatives, and antioxidants were also evaluated. The proposed electrochemical procedure was successfully applied to the determination of carmine food dye in spiked commercially available ice cream and soft drinks.
authors.affiliation: King Saud University, College of Science, Department of Chemistry, PO Box 2455, Riyadh-11451, Saudi Arabia. ahalgamdy@hotmail.com
authors.forename: Ahmad H
authors.initials: AH
authors.lastname: Alghamdi
authors.forename: Hamed M
authors.initials: HM
authors.lastname: Alshammery
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Abdalla
authors.forename: Ali F
authors.initials: AF
authors.lastname: Alghamdi
mesh_terms: D000085:Acetates / Q000032:analysis; D000327:Adsorption; D002138:Calibration; D002329:Carmine / Q000032:analysis*; D002623:Chemistry Techniques, Analytical; D004396:Coloring Agents / Q000032:analysis*; D004563:Electrochemistry / Q000379:methods; D004566:Electrodes; D004573:Electrolytes; D005505:Food Coloring Agents; D005506:Food Contamination; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D013997:Time Factors
chemical_list: D000085:Acetates; D004396:Coloring Agents; D004573:Electrolytes; D005505:Food Coloring Agents; D002329:Carmine