Data_Sheet_2_Enzyme-Free Electrochemical Sensors for in situ Quantification of Reducing Sugars Based on Carboxylated Graphene–Carboxylated Multiwalled Carbon Nanotubes–Gold Nanoparticle–Modified Electrode.docx

The reducing sugars of plants, including glucose, fructose, arabinose, galactose, xylose, and mannose, are not only the energy source of plants, but also have the messenger function of hormones in signal transduction. Moreover, they also determine the quality and flavor of agricultural products. Therefore, the in situ quantification of reducing sugars in plants or agriculture products is very important in precision agriculture. However, the upper detection limit of the currently developed sugar sensor is not high enough for in situ detection. In this study, an enzyme-free electrochemical sensor for in situ detection of reducing sugars was developed. Three-dimensional composite materials based on carboxylated graphene–carboxylated multi-walled carbon nanotubes attaching with gold nanoparticles (COOH-GR–COOH-MWNT–AuNPs) were formed and applied for the non-enzymatic determination of glucose, fructose, arabinose, mannose, xylose, and galactose. It was demonstrated that the COOH-GR–COOH-MWNT–AuNP-modified electrode exhibited a good catalysis behavior to these reducing sugars due to the synergistic effect of the COOH-GR, COOH-MWNT, and AuNPs. The detection range of the sensor for glucose, fructose, arabinose, mannose, xylose, and galactose is 5–80, 2–20, 2–50, 5–60, 2–40, and 5–40 mM, respectively. To our knowledge, the upper detection limit of our enzyme-free sugar sensor is the highest compared to previous studies, which is more suitable for in situ detection of sugars in agricultural products and plants. In addition, this sensor is simple and portable, with good reproducibility and accuracy; it will have broad practical application value in precision agriculture.

植物中的还原糖，包括葡萄糖、果糖、阿拉伯糖、半乳糖、木糖和甘露糖，不仅是植物的能量来源，而且具有激素在信号传导中的信使功能。此外，它们还决定了农产品的品质与风味。因此，在精准农业中，对植物或农产品中还原糖的现场定量显得尤为重要。然而，目前开发的糖传感器的上限检测限尚不足以满足现场检测的需求。在本研究中，一种无需酶的现场检测还原糖的电化学传感器被开发出来。基于羧化石墨烯-羧化多壁碳纳米管与金纳米粒子（COOH-GR-COOH-MWNT-AuNPs）的三维复合材料得以形成并应用于葡萄糖、果糖、阿拉伯糖、甘露糖、木糖和半乳糖的非酶检测。研究表明，COOH-GR-COOH-MWNT-AuNP修饰的电极由于COOH-GR、COOH-MWNT和AuNPs的协同效应，对这些还原糖表现出良好的催化活性。该传感器对葡萄糖、果糖、阿拉伯糖、甘露糖、木糖和半乳糖的检测范围分别为5-80、2-20、2-50、5-60、2-40和5-40 mM。据我们所知，与以往研究相比，我们开发的无需酶的糖传感器的上限检测限是最高的，更适合于农产品和植物中糖的现场检测。此外，该传感器结构简单、便于携带，具有良好的重现性和准确性；它在精准农业中将具有广泛的应用价值。