As an antineoplastic drug, methotrexate (MTX) is widely applied in cancer therapies; however it has potentially toxic activity, and thus the qualitative and quantitative determination of MTX is of great significance. In this paper, by using dopamine synchronously as a carbon and N source, N-doped hollow nanocarbon sphere (NHNC) hybrids were prepared via a simple self-polymerization method and used to construct a new electrochemical sensor for MTX. The prepared NHNC exhibits a uniform hollow nanostructure with high conductivity and electrocatalytic properties as well as large adsorption capacity and surface area, which are the key factors for improving the sensor sensitivity of MTX. For achieving highly sensitive determination of MTX, various conditions were optimized, and the final results show that the NHNC modified electrode has excellent sensing responses for MTX, and it has a wide linear range from 0.05 to 14.0 μM coupled with a low detection limit of 0.01 μM. Finally, studies on the reproducibility, stability and selectivity of the NHNC modified electrode show that the corresponding results are satisfactory.

中文翻译：

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N掺杂空心纳米碳球修饰电极高灵敏度电化学测定甲氨蝶呤

甲氨蝶呤（MTX）作为抗肿瘤药广泛应用于癌症治疗中。然而，它具有潜在的毒性作用，因此定性和定量测定MTX具有重要意义。本文以多巴胺为碳源和氮源同步使用，制备了氮掺杂空心纳米碳球（NHNC）杂化体。一种简单的自聚合方法，并用于构建用于MTX的新型电化学传感器。所制备的NHNC具有均匀的中空纳米结构，具有高电导率和电催化性能以及较大的吸附能力和表面积，这是提高MTX传感器灵敏度的关键因素。为了实现对MTX的高灵敏度测定，对各种条件进行了优化，最终结果表明NHNC修饰电极对MTX具有出色的感测响应，并且线性范围从0.05到14.0μM，检测限低至0.01微米 最后，对NHNC修饰电极的重现性，稳定性和选择性的研究表明，相应的结果令人满意。