Buettner G R
GSF Research Center, Institut für Strahlenbiologie, Neuherberg, F.R.G.
J Biochem Biophys Methods. 1988 May;16(1):27-40. doi: 10.1016/0165-022x(88)90100-5.
Trace amounts of adventitious transition metals in buffer solutions can serve as catalysts for many oxidative processes. To fully understand what role these metals may play it is necessary that buffer solutions be 'catalytic metal free'. We demonstrate here that ascorbate can be used in a quick and easy test to determine if near-neutral buffer solutions are indeed 'catalytic metal free'. In buffers which have been rendered free of catalytic metals we have found that ascorbate is quite stable, even at pH 7. The first-order rate constant for the loss of ascorbate in an air-saturated catalytic metal free solution is less than 6 X 10(-7) s-1 at pH 7.0. This upper limit appears to be set by the inability to completely eliminate catalytic metal contamination of solutions and glassware. We conclude that in the absence of catalytic metals, ascorbate is stable at pH 7.
缓冲溶液中痕量的外来过渡金属可作为许多氧化过程的催化剂。为了充分了解这些金属可能起的作用，缓冲溶液必须“无催化金属”。我们在此证明，抗坏血酸可用于一种快速简便的测试，以确定近中性缓冲溶液是否确实“无催化金属”。在已去除催化金属的缓冲溶液中，我们发现抗坏血酸相当稳定，即使在pH 7时也是如此。在pH 7.0的空气饱和无催化金属溶液中，抗坏血酸损失的一级速率常数小于6×10⁻⁷ s⁻¹。这个上限似乎是由无法完全消除溶液和玻璃器皿的催化金属污染所设定的。我们得出结论，在没有催化金属的情况下，抗坏血酸在pH 7时是稳定的。
