Titrimetric and Polarographic Determination of Carminic Acid and its Quantification in Cochineal (Dactylopius coccus) Extracts

The purity of synthetic carminic acid was quantified using potentiometric and conductimetric titrations, allowing its use as a secondary standard because there is not a primary one. Polarographic analysis (in ethanol-water 50:50, v/v) of carminic acid showed two reduction signals, each with a different number of electrons. The first reduction had more Nernstian behaviour and can be applied in analyses. Differential pulse polarography (DPP) produced a detection limit of 0.55 µg mL �1 . The results indicate that DPP can be used to