| Summary: | 博士 === 輔仁大學 === 化學系 === 106 === In recent years, emerging contaminants (ECs), out of regulation compounds such as estrogens can disturb the endocrine system of animals and human being. And it is reported that the metabolites of estrogens are biomarkers for breast cancer. For this reason, it is important to develop method to detect estrogens and their metabolites.
Electrochemical methods have attracted wide attention than others spectrometry due to their sensitivity, simplicity, low cost, small device and ease of miniaturization. Furthermore, it can be improved sensitivity by the modified electrode.
Screen-printed carbon electrode (SPCE) is inexpensive, ease, speed of mass production, and disposability electrode can be used to alternate glassy carbon electrode to build electrochemical transducer.
In this work, multi-walled carbon nanotubes (MWCNTs) couple with polytryptophan (PTRP), polyarginine (PARG), or poly(glutamic acid) (PGA) are used to develop modified screen-printed carbon electrodes to detect estrogens and their metabolites. In addition, α-cyclodextrin is used to help multi-walled carbon nanotubes to disperse in D.I. H2O. By using the differential pulse voltammetry (DPV), the electrodes can enhance signal up to 272.3, 330.7 and 331.9-folds to compare with bare electrode, respectively. The limit of detection for estrogens and their metabolites are 0.002 ~ 0.051 μM, 0.002 ~ 0.014 μM and 0.003 ~ 0.020 μM by modified electrodes, respectively.
And then, we apply high performance liquid chromatography (HPLC) and amperometry to detect estrogens and their metabolites by the modified electrodes. They can increase the signal up to 1.9-folds, and limit of detection are 0.055 ~ 0.297 μM, 0.032 ~ 0.120 μM, and 0.045 ~ 0.221 μM, respectively. Moreover, the modified electrodes are successfully used in the analysis of estrogens and their metabolites in waste water, urine, and serum samples. The modified electrodes can retain more than 81.5% original signal for 15 days and have good reproducibility for RSD < 9.32 %. Finally, those modified SPCEs are potential to detect estrogen and their metabolits in real sample.
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