Olson Mark P, Keating Loryn R, LaCourse William R
Department of Chemistry and Biochemistry, University of Maryland, Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, United States.
Anal Chim Acta. 2009 Oct 12;652(1-2):198-204. doi: 10.1016/j.aca.2009.06.051. Epub 2009 Jun 25.
Pulsed electrochemical detection (PED) following liquid chromatographic separation has been applied to the indirect determination of amino acids and proteins. Here, the adsorption of these analytes at noble metal electrodes is exploited to suppress the oxidation of polyols and carbohydrates under alkaline conditions to elicit an indirect response. Of the reagents tested, gluconic acid gave the best overall signal-to-noise values for the indirect detection of amino acids following high performance anion-exchange chromatography (HPAEC). Limits of detection of amino acids were found to be 2-30pmol using optimized potential-time waveforms at an Au electrode. Indirect PED provided much greater detection sensitivity toward amino acids than direct PED. Analytical sensitivity of indirect PED is a function of both the analyte's ability to adsorb to the electrode surface and its molecular size, which was demonstrated by the separation and detection of bovine serum albumin, ovalbumin, and myoglobin following gel-filtration chromatography (GFC).
液相色谱分离后的脉冲电化学检测（PED）已应用于氨基酸和蛋白质的间接测定。在此，利用这些分析物在贵金属电极上的吸附作用，在碱性条件下抑制多元醇和碳水化合物的氧化，从而产生间接响应。在所测试的试剂中，葡萄糖酸在高效阴离子交换色谱（HPAEC）后对氨基酸的间接检测给出了最佳的整体信噪比。在金电极上使用优化的电位-时间波形，发现氨基酸的检测限为2-30皮摩尔。间接PED对氨基酸的检测灵敏度比直接PED高得多。间接PED的分析灵敏度是分析物吸附到电极表面的能力及其分子大小的函数，这通过凝胶过滤色谱（GFC）后对牛血清白蛋白、卵清蛋白和肌红蛋白的分离和检测得到了证明。
