Margolis S A, Duewer D L
Analytical Chemistry Division, Chemical Science and Technology Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
Clin Chem. 1996 Aug;42(8 Pt 1):1257-62.
We demonstrate that total ascorbic acid (TAA, the sum of ascorbic acid and dehydroascorbic acid) in properly prepared human plasma is stable at -70 degrees C for at least 6 years when preserved with dithiothreitol. TAA in human plasma or serum preserved with metaphosphoric acid degrades slowly, at the rate of no more than 1% per year. As assessed from our stability data and from data obtained from 23 laboratories over a period of > 2 years, the intralaboratory repeatability of TAA measurement is approximately 2 mumol/L, irrespective of TAA concentration. Nonchromatographic analytical methods involving dinitrophenylhydrazine and 0-phenylenediamine yield biased results relative to chromatographic methods. Within groups of laboratories that use roughly similar analytical methods, the interlaboratory measurement reproducibility CV for TAA is 15%.
我们证明，在用二硫苏糖醇保存的情况下，妥善制备的人血浆中的总抗坏血酸（TAA，抗坏血酸和脱氢抗坏血酸之和）在-70℃下至少6年保持稳定。用偏磷酸保存的人血浆或血清中的TAA降解缓慢，每年降解率不超过1%。根据我们的稳定性数据以及从23个实验室在超过2年的时间里获得的数据评估，无论TAA浓度如何，TAA测量的实验室内重复性约为2 μmol/L。涉及二硝基苯肼和邻苯二胺的非色谱分析方法相对于色谱方法会产生有偏差的结果。在使用大致相似分析方法的实验室组中，TAA的实验室间测量再现性CV为15%。
