Ultrasensitive colorimetric detection of Cu2+ ion based on catalytic oxidation of L-cysteine.
Ultrasensitive colorimetric detection of Cu2+ ion based on catalytic oxidation of L-cysteine.
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DOI：
10.1016/j.bios.2014.08.058
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发表时间：
2015-02
影响因子：
12.6
通讯作者：
Kun Yin;Bowei Li;Xiaochun Wang;Weiwei Zhang;Lingxin Chen
中科院分区：
文献类型：
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作者：
Kun Yin;Bowei Li;Xiaochun Wang;Weiwei Zhang;Lingxin Chen
铜离子（Cu2+）作为人体必需元素，作为酶的辅助因子或结构组分参与多种代谢过程，在人体中发挥着重要作用。然而，过量摄取Cu2+离子会引起某些疾病的风险。因此，开发简单的方法来监测和检测Cu2+离子具有重要意义。本研究基于以下原理，研制了一种简便的超灵敏Cu2+离子比色传感器：l-半胱氨酸与1-氯-2,4-二硝基苯（CDNB）偶联形成黄色产物2,4-二硝基苯半胱氨酸（DNPC），在355nm处可测；然而，加入Cu2+离子后，由于Cu2+离子在O2存在下催化半胱氨酸-半胱氨酸氧化，DNPC的吸光度降低。从而实现了对Cu2+离子的比色检测。在0.1 M HEPES溶液中，90℃，50 min， pH为6.8，缓冲液为pH，温度为pH，比色传感器孵育时间为pH。在0.8 ~ 10 nM范围内具有良好的线性关系（r=0.996），检测检出率高达0.5 nM。对饮用水、湖水、海水和生物样品中的Cu2+离子进行了分析，结果与ICP-MS分析结果吻合较好。该比色传感器具有较高的灵敏度和选择性，适用于实际样品中Cu2+离子的测定。
As an essential element, copper ion (Cu2+) plays important roles in human beings for its participation in diverse metabolic processes as a cofactor and/or a structural component of enzymes. However, excessive uptake of Cu2+ion gives rise to the risk of certain diseases. So, it is important to develop simple ways to monitor and detect Cu2+ion. In this study, a simple, facile colorimetric sensor for the ultrasensitive determination of Cu2+ion was developed based on the following principle:l-cysteine and 1-chloro-2,4-dinitrobenzene (CDNB) could be conjugated to form the yellow product 2,4-dinitrophenylcysteine (DNPC), which was measurable at 355 nm; however, upon addition of Cu2+ion, the absorbance of DNPC would be decreased owing to the Cu2+ion catalytic oxidation ofl-cysteine tol-cystine in the presence of O2. Thus, the colorimetric detection of Cu2+ion could be achieved. The optimal pH, buffer, temperature and incubation time for the colorimetric sensor were obtained of pH 6.8 in 0.1 M HEPES solution, 90 °C and 50 min, respectively. A good linearity within the range of 0.8–10 nM (r=0.996) was attained, with a high detectability up to 0.5 nM. Analyses of Cu2+ion in drinking water, lake water, seawater and biological samples were carried out and the method performances were found to agree well with that obtained by ICP-MS. The developed simple colorimetric sensor proved applicable for Cu2+ion determination in real samples with high sensitivity and selectivity.