Four Derivative Spectrophotometric Methods for the Simultaneous Determination of Carmoisine and Ponceau 4R in Drinks and Comparison with High Performance Liquid Chromatography

Figure 4

(a) First derivative spectra between the mixture solution (6 μg mL⁻¹ Carmoisine + 6 μg mL⁻¹ Ponceau 4R) in the sample cell and different concentrations (2–10 μg mL⁻¹) of Ponceau 4R solutions in the reference cell. First derivative spectra between the mixture solution (6 μg mL⁻¹ Carmoisine + 6 μg mL⁻¹ Ponceau 4R) in the sample cell and 6 μg mL⁻¹ Ponceau 4R in the reference cell at balance points and comparison of these spectra with 6 μg mL⁻¹ concentration of Carmoisine (- - -) spectrum. (b) First derivative spectra between the mixture solution (6 μg mL⁻¹ Carmoisine + 6 μg mL⁻¹ Ponceau 4R) in the sample cell and different concentrations (2–10 μg mL⁻¹) of Carmoisine solutions in the reference cell. Derivative spectra between the mixture solution (6 μg mL⁻¹ Carmoisine + 6 μg mL⁻¹ Ponceau 4R) in the sample cell and 6 μg mL⁻¹ Carmoisine in the reference cell at balance points and comparison of these spectra with 6 μg mL⁻¹ concentration of Ponceau 4R (- - -) spectrum.

(a)

(b)