DETERMINATION OF SOME STRUCTURAL FEATURES OF PROCYANIDINS AND RELATED-COMPOUNDS BY PHOTODIODE-ARRAY DETECTION

In this work we have examined the use of a photodiode-array detector t o identify unknown peaks corresponding to procyanidins and related com pounds. The type of flavan-3-ol unit can be recognised from the absorp tion maximum (278.9 nm for catechin and epicatechin, and 270.6 nm for epigallocatechin), whereas the number of flavan-3-ol units does not af fect this parameter, The min-max distance (distance between the minimu m and the maximum in the original spectrum) decreases by 1.3 nm for ea ch catechin or epicatechin unit. Gallates of flavan-3-ol can be detect ed by reference to the value of the convexity interval (distance betwe en the inflection points before and after the maximum in the original spectrum).