ESTIMATION OF ZINC AND COPPER IN RAW AND COOKED LEGUMES - INTER-LABORATORY STUDY OF ATOMIC-ABSORPTION AND X-RAY-FLUORESCENCE SPECTROSCOPY

Zinc and copper are important nutrient elements in dry beans. The precision and accuracy of two instrumental methods, atomic absorption and x‐ray fluorescence spectroscopy, were compared and evaluated for the estimation of total copper and zinc in raw and cooked legume products. After calibration against National Bureau of Standards reference samples, corrected values obtained by both methods were essentially identical and in good agreements with values reported in the literature for random, analogous materials. Cooked standard and quick‐cooking beans both contained nutritionally significant amounts, but less zinc and copper than inedible, raw, dry beans. Copyright © 1979, Wiley Blackwell. All rights reserved