本文根据Landolt效应的H_2O_2-I~-体系的催化反应,研究了生物体中痕量钼的催化比色测定。反应中形成的I_2-淀粉兰色络合物的最大吸收峰为600nm,其摩尔吸收系数为2.11×10~4。Mo含量在0-0.40微克/15毫升范围内,遵循比尔定律。测定了文昌鱼,柑桔叶等中的痕量钼,得到满意的结果。 Based on the catalytic reaction of H 2 O 2 -I ~ - system with Landolt effect, this paper studied the catalytic colorimetric determination of trace molybdenum in organism. The maximum absorption peak of I_2-starch blue complex formed in the reaction was 600 nm, and its molar absorption coefficient was 2.11 × 10 ~ 4. The Mo content is in the range of 0-0.40 μg / 15 ml, following Beer’s law. The trace molybdenum in amphioxus, citrus leaves and the like was measured and satisfactory results were obtained.