Determination of thiols by capillary electrophoresis with amperometric detection at a coenzyme pyrroloquinoline quinone modified electrode
Determination of thiols by capillary electrophoresis with amperometric detection at a coenzyme pyrroloquinoline quinone modified electrode
复制标题
DOI：
10.1021/ac0108515
复制
发表时间：
2002-03-15
影响因子：
7.4
通讯作者：
Kirchhoff, JR
中科院分区：
文献类型：
--
作者：
Inoue, T;Kirchhoff, JR
建立了一种化学修饰电极，用于毛细管电泳分离后含硫醇化合物的灵敏和选择性检测。在PQQ存在下，吡咯电聚合时，将辅酶吡咯喹啉醌（PQQ）包埋在聚吡咯（PPy）基体上，在245- mom石墨电极上构建电极。PQQ作为一种高效的生物催化剂，在相对于未修饰电极的过电位大幅降低的情况下介导硫醇的氧化。此外，本设计利用了PQQ的ph依赖性可逆电化学特性，有利于优化分离和检测条件。采用PQQ/ py修饰电极作为端柱检测器，建立了同型半胱氨酸、半胱氨酸、n -乙酰半胱氨酸和谷胱甘肽的分离方法。4种硫醇的检出限分别为11、23、104和134 nM，质量检出限为0.29 ~ 3.48 fmol。PQQ/PPy电极也被发现在运行对运行，日常和电极对电极比较中具有很高的可重复性。该电极的效用被证明用于检测膳食补充剂和人类尿液中的半胱氨酸，结果与报道值非常一致。
A chemically modified electrode has been developed as a detector for the sensitive and selective determination of thiol-containing compounds following capillary electrophoresis separation. Electrodes were constructed by entrapment of the coenzyme pyrroloquinoline quinone (PQQ) into a polypyrrole (PPy) matrix on a 245-mum graphite electrode during electropolymerization of pyrrole in the presence of PQQ. PQQ serves as an efficient biocatalyst to mediate the oxidation of thiols at a substantially reduced overpotential relative to an unmodified electrode. Furthermore, this design takes advantage of the pH-dependent reversible electrochemical properties of PQQ, which facilitates optimization of separation and detection conditions. The PQQ/PPy-modified electrode was incorporated as an end-column detector, and a separation of homocysteine, cysteine, N-acetylcysteine, and glutathione was developed. Detection limits for these four thiols were determined to be 11, 23, 104, and 134 nM, respectively, with mass detection limits ranging from 0.29 to 3.48 fmol. The PQQ/PPy electrode was also found to be very reproducible in run-to-run, day-to-day, and electrode-to-electrode comparisons. The utility of this electrode was demonstrated for the detection of cysteine in dietary supplements and human urine, resulting in excellent agreement with reported values.