Thin layer cell behavior of CNT yarn and cavity carbon nanopipette electrodes: Effect on catecholamine detection
Thin layer cell behavior of CNT yarn and cavity carbon nanopipette electrodes: Effect on catecholamine detection
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DOI：
10.1016/j.electacta.2020.137032
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发表时间：
2020-11-20
影响因子：
6.6
通讯作者：
Venton, B. Jill
中科院分区：
文献类型：
--
作者：
Shao, Zijun;Puthongkham, Pumidech;Venton, B. Jill
碳纳米管纱线微电极（CNTYME）是碳纤维微电极（CFME）的替代品，具有有趣的电化学特性，因为分析物瞬间被捕获在CNT之间的空腔中。在这里，我们比较了快速扫描循环伏安法（FSCV）检测儿茶酚胺，包括多巴胺，去甲肾上腺素和肾上腺素，在CNTYMEs，CFMEs，以及腔碳纳米移液管电极（CNPEs）。在CFME中，电流在高FSCV重复频率下急剧减小。在CNTYME中，电流几乎与FSCV重复频率无关，因为分析物被捕获在CNT之间的缝隙中，因此电极就像薄层电池一样。在CFME处，由于分子内环化反应形成具有电活性的白儿茶酚胺而观察到小环化产物峰，并且这些峰对于仲胺肾上腺素最大。在CNTYME，更多的无色儿茶酚胺环化产物被检测到的所有的儿茶酚胺，因为增强的捕获效果，特别是在较高的重复率，反应发生更频繁，更多的产品被积累。对于肾上腺素，在100 Hz下，次级峰的电流大于初级氧化峰，并且在更快的扫描速率和500 Hz重复频率下观察到类似的趋势。最后，我们检查了CNPE，它也会暂时捕获神经递质。与CNTYME类似，在CNPE处，儿茶酚胺具有稳健的环化峰，特别是在高重复率下。因此，CNTYME和CNPE具有有利于高时间分辨率测量的薄层细胞行为，但环化反应使儿茶酚胺CV复杂化。然而，这些额外的峰可用于区分分析物，特别是肾上腺素和去甲肾上腺素。(C)2020爱思唯尔有限公司保留所有权利。
Carbon nanotube yarn microelectrodes (CNTYMEs) are an alternative to carbon-fiber microelectrodes (CFMEs) with interesting electrochemical properties because analyte is momentarily trapped in cavities between the CNTs. Here, we compare fast-scan cyclic voltammetry (FSCV) detection of catecholamines, including dopamine, norepinephrine, and epinephrine, at CNTYMEs, CFMEs, as well as cavity carbon nanopipette electrodes (CNPEs). At CFMEs, current decreases dramatically at high FSCV repetition frequencies. At CNTYMEs, current is almost independent of FSCV repetition frequency because the analytes are trapped in the crevices between CNTs, and thus the electrode acts like a thin-layer cell. At CFMEs, small cyclization product peaks are observed due to an intramolecular cyclization reaction to form leucocatecholamine, which is electroactive, and these peaks are largest for the secondary amine epinephrine. At CNTYMEs, more of the leucocatecholamine cyclization product is detected for all catecholamines because of the enhanced trapping effects, particularly at higher repetition rates where the reaction occurs more frequently and more product is accumulated. For epinephrine, the secondary peaks have larger currents than the primary oxidation peaks at 100 Hz, and similar trends are observed with faster scan rates and 500 Hz repetition frequencies. Finally, we examined CNPEs, which also momentarily trap neurotransmitters. Similar to CNTYMEs, at CNPEs, catecholamines have robust cyclization peaks, particularly at high repetition rates. Thus, CNTYMEs and CNPEs have thin layer cell behavior that facilitates high temporal resolution measurements, but catecholamines CVs are complicated by cyclization reactions. However, those additional peaks could be useful in discriminating the analytes, particularly epinephrine and norepinephrine. (C) 2020 Elsevier Ltd. All rights reserved.