Chromatographic method to isolate valuable ingredients of saffron extracts

The valuable spice saffron contains several valuable ingredients. This paper presents results of isolating picrocrocin, crocins I and crocin II from extracts generated of two grades of saffron using reversed phase chromatography exploiting step gradients. After performing a preliminary feasibility study using a low grade feed, isocratic pulse experiments were conducted to estimate and correlate the adsorption equilibrium constants for the target components for different constant mobile phase compositions. A graphical representation of the development of the chromatograms based on the equilibrium theory of chromatography was exploited for the design of a simple step gradient processes. The solvent gradient conditions identified were implemented and found to be applicable to efficiently solve the separation problem. Classical scale up rules were used to increase the productivity using a larger column volume. The tree target compounds could be isolated with purities of 97.3 %, 98.3 %, and 96.6 %, respectively. The component specific productivity of provision was for the feed processed between 0.6 and 1.7 g/h/L, which indicates potential for large-scale application of the separation method developed.