Evaluation of different detection modes for the analysis of procyanidins in leaves and flowers of Crataegus spp. Part I. Diode array and electrochemical detection

Diode array and single electrode electrochemical detection were evaluated f or their use in the analysis of (-)-epicatechin and oligomeric procyanidins in reference solutions and extracts of leaves and flowers of Crataegus spp , Linearity of regression curves was good for both detection modes. Diode a rray detection was found to be more selective but less sensitive than elect rochemical detection, The absorbance ratio 220/280 nm gives information on the degree of polymerization in reference solutions, In the presence of mat rix no additional structural information can be obtained from the absorbanc e ratios due to high standard deviations. Quantitative evaluation in terms of monomer equivalents using electrochemical detection leads to an underest imation of the contents of procyanidin dimers, but it is applicable using d etection at 280 nm, in view of the better selectivity and the easier handli ng, diode array detection is recommended for the analysis of procyanidins i n complex matrices. Copyright (C) 2000 John Wiley & Sons, Ltd.