Resumo

REYES-SALAS, Octavio et al. Titrimetric and Polarographic Determination of Carminic Acid and its Quantification in Cochineal (Dactylopius coccus) Extracts. J. Mex. Chem. Soc [online]. 2011, vol.55, n.2, pp.88-93. ISSN 1870-249X.

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 determine carminic acid content in cochineal extracts.

Palavras-chave : Carminic acid; acid-basic titration; electrochemical determination; cochineal extract; polarography.