Buettner G R
ESR Center, University of Iowa, Iowa City 52242.
Free Radic Res Commun. 1990;10(1-2):5-9. doi: 10.3109/10715769009145927.
Catalytic transition metals are an absolute requirement for the aerobic oxidation of ascorbate monoanion. Thus, for example, the concentration of iron can be determined by the metal-dependent rate of ascorbate oxidation in near-neutral solutions. The lower limit of detection of iron, as Fe(III)EDTA, by monitoring the decrease in absorbance at 265 nm of ascorbate is about 200 nM. However, by measuring the concentration of the ascorbyl radical by ESR spectroscopy the lower limit is about 10 nM. Using these assays, I have shown that the typical microliter laboratory syringe can introduce significant iron into solutions. Thus, for studies involving iron, these two tests can be used to determine the amount of contaminating iron in reagents as well as iron from other sources such as laboratory equipment.
催化过渡金属是抗坏血酸单阴离子有氧氧化的绝对必要条件。因此，例如，铁的浓度可以通过近中性溶液中金属依赖的抗坏血酸氧化速率来测定。通过监测抗坏血酸在265nm处吸光度的降低来检测作为Fe(III)EDTA的铁的检测下限约为200 nM。然而，通过电子自旋共振光谱法测量抗坏血酸自由基的浓度，下限约为10 nM。使用这些测定方法，我已经表明，典型的微升实验室注射器会将大量铁引入溶液中。因此，对于涉及铁的研究，这两种测试可用于确定试剂中以及来自实验室设备等其他来源的污染铁的量。
