<b>Graphene/Amorphous MIL-101(Cr)-NH</b>_{<strong>2</strong>}<b> Double Layer Composite for Nonenzymatic Sweat Glucose Sensing by Voltammetry and Chronoamperometry</b>

Herein, we report a novel electrochemical sensor for determining glucose in sweat, employing a graphene/metal-organic framework (MOF) as a modifier for stainless steel (SS) electrode. The MOF structures, MIL-101(Cr), MIL-101(Cr)-NO₂, andMIL-101(Cr)-NH₂, were hydrothermally synthesized and then characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, N₂ adsorption/desorption isotherms, and scanning electron microscopy (SEM). XRD and SEM results proved the formation of the crystalline MIL-101(Cr) and MIL-101(Cr)-NO₂, and the amorphousMIL-101(Cr)-NH₂. Additionally, FT-IR and isotherms confirmed their composition and mesoporosity, respectively. The amorphous MIL-101(Cr)-NH₂showed the best electrocatalytic activity towards glucose oxidation among the fabricated MOFs. The electrocatalytic activity was also boosted after incorporating conductive graphene. Under optimized conditions, graphene/MIL-101(Cr)-NH₂/SS was used for glucose determination using square wave voltammetry and chronoamperometry with detection limits of 0.004 and 0.01 mM, respectively. Moreover, the modified electrode showed acceptable recovery values when it was applied to detect glucose in artificial sweat samples.本研究报道了一种用于汗液中葡萄糖检测的新型电化学传感器，以石墨烯/金属有机框架（metal-organic framework, MOF）作为不锈钢（stainless steel, SS）电极的修饰材料。本研究选取三种MOF结构，即MIL-101(Cr)、MIL-101(Cr)-NO₂以及MIL-101(Cr)-NH₂，通过水热法合成，并采用X射线衍射（X-ray diffraction, XRD）、傅里叶变换红外（Fourier transform infrared, FT-IR）光谱法、氮气吸附/脱附等温线以及扫描电子显微镜（scanning electron microscopy, SEM）对其进行表征。X射线衍射与扫描电子显微镜表征结果证实，MIL-101(Cr)与MIL-101(Cr)-NO₂为晶态结构，而MIL-101(Cr)-NH₂则为无定形态。此外，傅里叶变换红外光谱与氮气吸附/脱附等温线分别验证了所合成材料的化学组成与介孔特性。在所制备的各类MOF材料中，无定形态的MIL-101(Cr)-NH₂对葡萄糖氧化展现出最优的电催化活性。引入具有导电性的石墨烯后，该材料的电催化活性进一步提升。在优化后的实验条件下，采用石墨烯/MIL-101(Cr)-NH₂/SS修饰电极，通过方波伏安法与计时电流法实现葡萄糖的检测，二者的检出限分别为0.004 mM与0.01 mM。此外，将该修饰电极应用于人工汗液样品中的葡萄糖检测时，获得了令人满意的回收率。