Zinellu Angelo, Sotgia Salvatore, Deiana Luca, Carru Ciriaco
Department of Biomedical Sciences, Chair of Clinical Biochemistry, University of Sassari, Viale San Pietro 43/B, I-07100 Sassari, Italy.
J Biochem Biophys Methods. 2006 Jun 30;67(2-3):95-105. doi: 10.1016/j.jbbm.2006.01.006. Epub 2006 Feb 20.
We have recently described a new capillary electrophoresis assay to measure serum ascorbic and uric acids in which a baseline separation of peaks was obtained in less than 4 min by using a 60.2 cm x 75 microm uncoated capillary with a 100 mmol/L sodium borate running buffer pH 8. Since during sample preparation AA is rapidly oxidized, we employed our new capillary electrophoresis method to analyze the pre-analytical factors affecting its stability. In particular we evaluated how the standard mix preparation, the blood collection (plasma EDTA or serum) and the plasma protein precipitation influence the results of analysis. Our data suggest that standard ascorbate must be dissolved in a solution containing cysteine and EDTA in order to avoid oxidation and that EDTA blood collection is better than serum for AA measurement. Moreover, the type and the quantity of the precipitating compound are critical parameters to obtain a complete recovery of analytes. We performed AA and UA analysis in 32 healthy volunteers with the optimized experimental conditions by using our capillary electrophoresis method and a reference CE assay. Obtained data were compared to Bland-Altman test to verify the accuracy of our CZE method.
我们最近描述了一种用于测量血清中抗坏血酸和尿酸的新型毛细管电泳测定法，通过使用一根60.2厘米×75微米的未涂层毛细管和pH值为8的100毫摩尔/升硼酸钠运行缓冲液，在不到4分钟内实现了峰的基线分离。由于在样品制备过程中抗坏血酸（AA）会迅速氧化，我们采用新的毛细管电泳方法来分析影响其稳定性的分析前因素。特别是，我们评估了标准混合物的制备、血液采集（血浆乙二胺四乙酸（EDTA）或血清）以及血浆蛋白沉淀如何影响分析结果。我们的数据表明，标准抗坏血酸盐必须溶解在含有半胱氨酸和EDTA的溶液中以避免氧化，并且对于AA测量，采集EDTA血液比采集血清更好。此外，沉淀化合物的类型和数量是实现分析物完全回收的关键参数。我们使用毛细管电泳方法和参考毛细管电泳测定法，在优化的实验条件下对32名健康志愿者进行了AA和尿酸（UA）分析。将获得的数据与布兰德 - 奥特曼检验进行比较，以验证我们的毛细管区带电泳（CZE）方法的准确性。
