本文利用亚甲基蓝（MB）颜色可逆调控技术，研究了抗坏血酸（AA）的氧化动力学及MB的影响。蓝色MB与AA快速反应生成无色的还原态亚甲基蓝（LMB），随后通入O2使LMB氧化回复始态的MB，并通过MB在664 nm的特征吸收峰监测AA的氧化。在饱和O2氛围中，AA的氧化呈现出零级反应动力学特征，其反应速率常数为0.193 mol L1 s1；MB不仅能作为检测AA的光谱探针，而且能促进AA的氧化，使AA的氧化反应活化能降低了35.5%，速率常数增大了1.5倍。此外，该方法应用于片剂中AA的含量测定和氧化评价，显示了2.1%的相对标准偏差，具有成本低、灵敏度高、重现性好的特点。
A redox-driven reversible color tuning technique has been successfully used to investigate the oxidation kinetics of ascorbic acid (AA) and the effects of MB under O2-rich conditions. The blue MB is first reduced to form colorless leucomethylene (LMB) by adding AA, in which LMB is subsequently oxidized to recover MB by injecting O2, and AA is simultaneously monitored by characteristic absorption peaks of MB at 664 nm. It is found that the zero-order oxidation reaction of AA has rate constants of 0.193 mol L1 s1 under oxygen-saturated atmospheres. MB not only is a good spectral probe, but also leads to a 35.5% decrease in the activation energy barrier and a 1.5-fold increase in the rate constant for the oxidation reaction of AA. Moreover, the proposed approach is applied to the determination and oxidation evaluation of AA in tablet dosage forms, showing the relative standard deviation (RSD) of 2.1%, and the merits of low cost, high sensitivity and good reproducibility.