Hydroquinone-Based Derivatization Reagents for the Quantitation of Amines Using Electrochemical Detection
作者:Mark J. Rose、Susan M. Lunte、Robert G. Carlson、John F. Stobaugh
DOI:10.1021/ac981236c
日期:1999.6.1
Two new reagents, NDTE (2,5-dihydroxyphenylacetic acid, 2,5-bis-tetrahydropyranyl ether p-nitrophenyl ester) and HLTE (homogentisic γ-lactone tetrahydropyranyl ether), are described for the chemical derivatization of primary and/or secondary amines to form an electrochemically active product. These reagents undergo reaction with the aforementioned analytes to form a product possessing the hydroquinone moiety, thus allowing for reversible electrochemical detection at mild oxidation potentials. The reactivity of each reagent was demonstrated by using N-ethylbenzylamine (EBzA) and the dipeptide isoleucine leucine methyl ester as model analytes. The investigation included the isolation and identification of the intermediates and final products from derivatization of EBzA. These isolated standards were subsequently characterized with respect to electrochemical properties by means of cyclic voltammetry. In LC-EC experiments, the concentration limit of detection (CLOD) of the purified EBzA product was determined to be 5 nM (100 fmol) at a detection potential of +200 mV vs Ag/AgCl ([Cl-] = 3 M). The CLOD values obtained by LC-EC after derivatization of aqueous solutions of EBzA and Ile-Leu-OMe with NDTE were 25 nM (250 fmol) and 250 nM (2.5 pmol), respectively.
本文介绍了 NDTE(2,5-二羟基苯乙酸,2,5-双四氢吡喃基醚对硝基苯酯)和 HLTE(均质γ-内酯四氢吡喃基醚)这两种新试剂,用于对伯胺和/或仲胺进行化学衍生以形成具有电化学活性的产物。这些试剂与上述分析物发生反应,形成具有对苯二酚分子的产物,从而可以在温和的氧化电位下进行可逆电化学检测。以 N-乙基苄胺(EBzA)和二肽异亮氨酸亮氨酸甲酯为模型分析物,证明了每种试剂的反应性。研究包括分离和鉴定 EBzA 衍生过程中的中间产物和最终产物。随后通过循环伏安法对这些分离出的标准品进行了电化学特性鉴定。在 LC-EC 实验中,纯化的 EBzA 产物的检测浓度限(CLOD)被确定为 5 nM(100 fmol),检测电位为 +200 mV vs Ag/AgCl([Cl-] = 3 M)。用 NDTE 对 EBzA 和 Ile-Leu-OMe 的水溶液进行衍生后,通过 LC-EC 测得的 CLOD 值分别为 25 nM(250 fmol)和 250 nM(2.5 pmol)。