Recently, graphene nanosheet has attracted the most attention for the potential applications in various electrochemical sensing fields to biomedical diagnosis and therapy due to its large theoretical specific surface area, unique physical and electrical properties. In this paper, a newly sensitive and selective modified carbon paste electrodes (MCPEs) were developed for the determination of alfuzosin hydrochloride (ALF.HCl) in pharmaceutical preparation and biological fluid samples. The paste of these sensors was prepared by mixing alfuzosin phosphomolybdate (ALF-PMA) and alfuzosin tetraphenylborate (ALF-TPB) ion pairs as recognition reagents with different supporting matrices including graphite powder alone or different ratios of graphite to graphene powders and plasticizer of a relatively high dielectric constant. The sensor prepared based on graphite alone as a supporting matrix gave Nernstian slope values of 56.7 ± 0.75 and 51.1 ± 1.11 mV decade⁻¹ for electrode modified with ALF-PMA and ALF-TPB ion pairs, respectively, in the concentration range from 1.0 × 10⁻⁵ to 1.0 × 10⁻² mol L⁻¹ at 25 °C, and the response of the electrode was found to be independent on pH in the range of 2.0–5.0. The Nernstian slope for ALF-TPB modified carbon paste electrode was improved to be 55.8 ± 1.07 mV decade⁻¹ upon mixing graphene with graphite in the paste and showed pH independence in the range of 2.0–6.0. The proposed sensors were successfully applied for the determination of ALF.HCl in pure, biological fluid samples and pharmaceutical preparation using the direct potentiometric and standard addition methods. Finally, the results obtained using the proposed sensors were compared with those from the official method.

中文翻译：

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经验证的电位滴定法测定药物和生物液体样品中的盐酸阿夫唑嗪

近年来，石墨烯纳米片因其理论比表面积大，独特的物理和电学性质而在生物医学诊断和治疗的各种电化学传感领域中的潜在应用吸引了最多的关注。本文开发了一种新的灵敏且选择性的修饰碳糊电极（MCPE），用于测定药物制剂和生物液体样品中的盐酸阿夫唑嗪（ALF.HCl）。这些传感器的糊剂是通过将阿夫唑嗪磷钼酸盐（ALF-PMA）和阿夫唑嗪四苯基硼酸酯（ALF-TPB）离子对作为识别试剂与不同的支持基质混合而成的，这些基质包括单独的石墨粉或不同比例的石墨与石墨烯粉和相对比例的增塑剂高介电常数。在25°C下，用ALF-PMA和ALF-TPB离子对修饰的电极的^-1浓度范围为1.0×10 ^-5至1.0×10 ^-2 mol L ^-1，电极的响应为被发现与pH无关，范围为2.0-5.0。ALF-TPB改性碳糊电极的Nernstian斜率提高到55.8±1.07 mV·十^-1石墨烯和石墨在糊中混合后，pH无关性在2.0–6.0范围内。所提出的传感器已成功应用于直接电位法和标准添加法测定纯生物流体样品和药物制剂中的ALF.HCl。最后，将使用建议的传感器获得的结果与来自官方方法的结果进行比较。