MnO₂／延展石墨電化學葡萄糖感測

MnO2/Extended Graphite for electrochemical glucose sensing

本研究以電化學活化方式調控延展石墨（gra-L、gra-M、gra-H）表面缺陷與含氧官能基密度，並透過自發氧化還原反應於其表面均勻沉積三維分級花狀結構的MnO2。形貌與結構分析顯示，高活化度gra-H具最高比表面積與均勻反應位點，形成由多層超薄奈米片構成的導電網路。XPS與XAS結果證實，MnO2/gra-H擁有較高比例的Mn4+及Mn–O–C共價鍵結，提升電子傳輸效率與氧化還原活性。於0.1 M NaOH溶液中，MnO2/gra- H電極對葡萄糖展現高靈敏度（43μA mM-1 cm-2）、低檢出極限（0.081 mM）、良好選擇性與長期穩定性。進一步採用LC–MS/MS驗證其在合成血清中的檢測結果，兩種方法於全濃度範圍內呈高度一致性（R²> 0.99，誤差±10%內），證明MnO2/gra-H在複雜基質中亦具高精確度與可靠性。本研究展示MnO2/gra-H於高性能電化學葡萄糖感測的潛力，並可延伸應用於生物檢測與環境監測領域。

In this study, electrochemically activated extended graphite (gra-L, gra-M, gra-H) was prepared with tunable surface defects and oxygen-containing functional groups, followed by the uniform deposition of three-dimensional hierarchical flower-like MnO2 via a spontaneous redox reaction. Morphological and structural analyses revealed that highly activated gra-H possessed the largest specific surface area and the most uniformly distributed reactive sites, forming a conductive network of interconnected ultrathin nanosheets. XPS and XAS results confirmed that MnO2/gra-H exhibited a higher proportion of Mn4+ species and Mn–O–C covalent bonding, enhancing electron transport efficiency and redox activity. In 0.1 M NaOH solution, the MnO2/gra-H electrode demonstrated high sensitivity (43μA mM-1 cm-2), a low detection limit (0.081 mM), excellent selectivity, and long-term stability for glucose oxidation. The accuracy of glucose quantification in synthetic serum was further validated using LC–MS/MS, showing excellent agreement between electrochemical and mass spectrometric results across the full concentration range (R²> 0.99, deviation within±10 %). These findings confirm that MnO2/gra-H maintains high precision and reliability even in complex matrices. This work highlights the potential of MnO2/gra-H for high-performance electrochemical glucose sensing and its broader applicability in biosensing, environmental monitoring, and other multifunctional electrochemical technologies.