Analytical performance
Under the optimized conditions, the analytical parameters of
the proposed method for carmine determination were calculated.
Calibration curve was obtained in the range of 0.04–5.0 lg mL1.
Equation and regression coefficient are A = 0.245C + 0.06 and
0.9995, respectively. The limit of detection (LOD) based on
S/N = 3 was 0.012 lgmL1 and the relative standard deviation
(RSD) in low concentration level (0.05 lgmL1) of carmine was
4.8% (n = 7). The method was applied to the determination of carmine
in several food samples such as smarties and soft drinks.