This article describes an attempt to develop a sensor based on multi-frequency immittance spectroscopy for the determination of methotrexate (MTX) in blood serum using gold electrodes modified with antibodies. The attachment of antibodies was monitored with electrochemical immittance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS). The EIS measurements of MTX resulted in a data matrix of size 39 × 55. The data were analysed using multivariate data analysis and showed a concentration dependence and time dependence that could be separated. This allowed the calculation of a multivariate calibration model. The model showed good linear behavior on a logarithmic scale offering a detection limit of 5 × 10-12 mol L-1.

中文翻译：

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使用多频电化学导抗谱和多元数据分析测定加标人血清中的甲氨蝶呤

本文介绍了开发基于多频导抗光谱的传感器的尝试，该传感器使用经抗体修饰的金电极测定血清中的甲氨蝶呤 (MTX)。用电化学导抗谱 (EIS) 和 X 射线光电子能谱 (XPS) 监测抗体的附着。MTX 的 EIS 测量产生了一个大小为 39 × 55 的数据矩阵。使用多变量数据分析对数据进行了分析，并显示出可以分离的浓度依赖性和时间依赖性。这允许计算多变量校准模型。该模型在对数尺度上显示出良好的线性行为，提供 5 × 10-12 mol L-1 的检测限。