ELECTROCATALYTIC AND ANALYTICAL RESPONSE OF COBALT PHTHALOCYANINE CONTAINING CARBON PASTE ELECTRODES TOWARD SULFHYDRYL COMPOUNDS
ELECTROCATALYTIC AND ANALYTICAL RESPONSE OF COBALT PHTHALOCYANINE CONTAINING CARBON PASTE ELECTRODES TOWARD SULFHYDRYL COMPOUNDS
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DOI：
10.1021/ac00280a007
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发表时间：
1985-01-01
影响因子：
7.4
通讯作者：
BALDWIN, RP
中科院分区：
文献类型：
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作者：
HALBERT, MK;BALDWIN, RP
在制备碳糊电极的石墨粉/Nujol油基质中加入钴酞菁(CoPC)构建的化学修饰电极，可以催化半胱氨酸、同型半胱氨酸、/V-乙酰半胱氨酸和谷胱甘肽等含硫化合物的电氧化。在0.75-0.85V与Ag/AgCI的条件下发生了巯基氧化，这与CoPC在溶液中和加入碳糊后的氧化电位相同。在使用CoPC电极作为检测电极时，CoPC电极可以在相同的外加电位值下对化合物进行检测。半胱氨酸、N-乙酰半胱氨酸和同型半胱氨酸的检出限为2.7pmoL，电极响应线性范围达270pmoL。不同的碳糊表面以标准方式更新产生的色谱峰电流的重现性为7%。近年来，具有特定化学功能的电极被证明在许多应用领域具有明显的优势，包括电合成、电催化和光电化学(1，2)。原则上，这种化学修饰电极(CME)也应该能够在电分析领域提供更好的性能。然而，迄今为止，涉及为这种目的利用海洋生态系统的情况尚未被广泛记录，尽管可能会产生潜在的好处。CMEs的重要性质之一是其催化氧化或还原溶质物种的能力，这些溶质物种在未经修饰的表面表现出高的过电压，因此不适合于通过传统的电化学方法进行定量测定。由于这种CME电催化的主要作用是降低催化氧化还原体系的电解所需的电位，因此这些电极应该可以直接应用于各种分析场合。特别是，它们的使用将极大地提高液相色谱(LCEC)中电化学检测技术的能力
Chemically modified electrodes, constructed by Incorporating cobalt phthalocyanine (CoPC) Into the graphite powder/Nujol oil matrix used to fabricate conventional carbon paste electrodes, were shown to catalyze the electrooxidation of sulfhydryl-contalning compounds Including cysteine, homocysteine,/V-acetylcysteine, and glutathione. The sulfhydryl oxidation occurred at 0.75-0.85 V vs. Ag/AgCI, the same potential observed for the CoPC oxidation both In solution and after addition to the carbon paste. When used as the sensing electrodes In amperometric detection following liquid chromatography, the CoPC electrodes permitted detection of the compounds at similar values of applied potential. Detection limits of 2.7 pmol were obtained for cysteine, N-acetyl-cysteine, and homocysteine; and electrode response was linear up to 270 pmol Injected. Different carbon paste sur-faces renewed In the standard manner yielded chromatographic peak currents with a reproducibility of 7%.In recent years, electrodes possessing specific chemical functionalities intentionally linked to their surface have been demonstrated to possess distinct advantages over conventional electrode substrates in numerous application areas including electrosynthesis, electrocatalysis, and photoelectrochemistry (1, 2). In principle, such chemically modified electrodes (CMEs) should also be able to provide enhanced performance in the area of electroanalysis as well. However, to date, in-stances involving the utilization of CMEs for such purposes have not been extensively documented despite thepotential advantages which might be expected to accrue. One of the important properties of CMEs which has been the object of considerable study has been their ability to catalyze the oxidation or reduction of solute species which exhibit high overvoltages at unmodified surfaces and conse-quently are not ideally suited to quantitative determination via conventional electrochemical approaches. Since the major effect of such CME electrocatalysis consists of the lowering of the potential required for the electrolysis of the catalyzed redox system, these electrodes should possess direct application in a variety of analytical situations. In particular, their use should greatly improve the capabilities of electrochemical detection techniques in liquid chromatography (LCEC) where