Formation and HPLC analysis of the natural lake pigment obtained from madder (Rubia Tinctoruml.)

Abstract

In this work, madder lake pigments, aluminium-madder, tin-madder and iron-madder, were obtained by the reaction of KA1(SO4) 2.12H2O, FeSO4.7H2O and SnCl 2.2H2O solutions with madder. High performance liquid chromatography (HPLC) with diode-array detection (DAD) method was utilized for the identification of the lake pigments. Reversed-phase HPLC with diode-array UV-Vis spectrophotometric detection was used in this identification. The extraction of dyestuffs from the lake pigments was carried out with HC1 / methanol / water (2:1:1; v/v/v) solution. From the results of the HPLC analysis of the madder lake pigments, it was determined that the alizarin present in the lake pigments was precipitated by Al(III), Fe(II) and Sn(II).