生物体系中许多氧化还原反应是按照电化学机理进行的。例如有机体中的固氮过程就经历一系列复杂的电子传递步骤。为了解固氮过程的电子传递机理,已利用吸收光谱、电子顺磁共振谱、电位滴定和定电位电量法等多种方法测定钼铁蛋白的氧还电位,但所得结果很不一致。定电位电量法不需要外加强的氧化剂或还原剂,避免出此引 Many redox reactions in biological systems follow electrochemical mechanisms. For example, nitrogen fixation in organisms undergoes a series of complex electron transfer steps. In order to understand the electron transfer mechanism of nitrogen fixation process, the oxygen potential of molybdenum ferritin has been determined by absorption spectroscopy, electron paramagnetic resonance spectroscopy, potentiometric titration and potentiometric method, but the results obtained are very inconsistent. Potentiometric method does not require additional strong oxidant or reductant to avoid this lead