Materials Science and Engineering Program, University of California, Riverside, CA 92521, USA.
Department of Chemical and Environmental Engineering, University of California, Riverside, CA 92521, USA.
Sensors (Basel). 2021 Jan 28;21(3):883. doi: 10.3390/s21030883.
Linker-free magnetite nanoparticles (FeONPs)-decorated gold nanoparticles (AuNPs) were grown using a new protocol that can be used as a new platform for synthesis of other intact metal-metal oxide nanocomposites without the need for linkers. This minimizes the distance between the metal and metal oxide nanoparticles and ensures the optimum combined effects between the two material interfaces. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy confirmed the successful synthesis of the FeO-Au nanocomposite, without any change in the magnetite phase. Characterization, using transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy, revealed the composite to consist of AuNPs of 70 ± 10 nm diameter decorated with tiny 10 ± 3 nm diameter FeONPs in Au:Fe mass ratio of 5:1. The prepared FeO-Au nanocomposite was embedded in ionic liquid (IL) and applied for the modification of glassy carbon electrode (GCE) for the electrochemical detection of As(III) in water. By combining the excellent catalytic properties of the AuNPs with the high adsorption capacity of the tiny FeONPs towards As(III), as well as the good conductivity of IL, the FeO-Au-IL nanocomposite showed excellent performance in the square wave anodic stripping voltammetry detection of As(III). Under the optimized conditions, a linear range of 1 to 100 μg/L was achieved with a detection limit of 0.22 μg/L (S/N = 3), and no interference from 100-fold higher concentrations of a wide variety of cations and anions found in water. A very low residual standard deviation of 1.16% confirmed the high precision/reproducibility of As(III) analysis and the reliability of the FeO-Au-IL sensing interface. Finally, this proposed sensing interface was successfully applied to analyzing synthetic river and wastewater samples with a 95-101% recovery, demonstrating excellent accuracy, even in complex synthetic river and wastewater samples containing high concentrations of humic acid without any sample pretreatments.
无连接剂的磁铁矿纳米粒子（FeONPs）修饰的金纳米粒子（AuNPs）是使用一种新的方案生长的，该方案可作为合成其他完整的金属-金属氧化物纳米复合材料的新平台，而无需连接剂。这最大限度地减小了金属和金属氧化物纳米粒子之间的距离，并确保了两种材料界面之间的最佳组合效果。X 射线衍射（XRD）和傅里叶变换红外（FTIR）光谱证实了 FeO-Au 纳米复合材料的成功合成，而磁铁矿相没有任何变化。使用透射电子显微镜（TEM）、扫描电子显微镜（SEM）和能量色散 X 射线（EDX）光谱进行的表征表明，该复合材料由 70 ± 10nm 直径的 AuNPs 组成，这些 AuNPs 上装饰有 10 ± 3nm 直径的 FeONPs，Au:Fe 质量比为 5:1。制备的 FeO-Au 纳米复合材料嵌入在离子液体（IL）中，并应用于修饰玻碳电极（GCE），用于水中 As(III)的电化学检测。通过将 AuNPs 的优异催化性能与 FeONPs 对 As(III)的高吸附能力以及 IL 的良好导电性相结合，FeO-Au-IL 纳米复合材料在 As(III)的方波阳极溶出伏安法检测中表现出优异的性能。在优化条件下，线性范围为 1 至 100μg/L，检测限为 0.22μg/L（S/N = 3），并且在水中发现的 100 倍更高浓度的多种阳离子和阴离子没有干扰。1.16%的低标准偏差证实了 As(III)分析的高精度/重现性和 FeO-Au-IL 传感界面的可靠性。最后，该传感界面成功应用于分析合成的河水和废水样品，回收率为 95-101%，即使在含有高浓度腐殖酸的复杂合成河水和废水中，也具有出色的准确性，无需进行任何样品预处理。
