Wan Khalid Wan Elina Faradilla, Mat Arip Mohamad Nasir, Jasmani Latifah, Lee Yook Heng
School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia.
Faculty of Applied Sciences, Universiti Teknologi MARA Negeri Sembilan, Kuala Pilah Campus, Pekan Parit Tinggi, Kuala Pilah 72000, Negeri Sembilan, Malaysia.
Sensors (Basel). 2019 Jun 18;19(12):2726. doi: 10.3390/s19122726.
A new cellulose nanocrystal-reduced graphene oxide (CNC-rGO) nanocomposite was successfully used for mediatorless electrochemical sensing of methyl paraben (MP). Fourier-transform infrared spectroscopy (FTIR) and field-emission scanning electron microscopy (FESEM) studies confirmed the formation of the CNC-rGO nanocomposite. Cyclic voltammetry (CV) studies of the nanocomposite showed quasi-reversible redox behavior. Differential pulse voltammetry (DPV) was employed for the sensor optimization. Under optimized conditions, the sensor demonstrated a linear calibration curve in the range of 2 × 10-9 × 10 M with a limit of detection (LOD) of 1 × 10 M. The MP sensor showed good reproducibility with a relative standard deviation (RSD) of about 8.20%. The sensor also exhibited good stability and repeatability toward MP determinations. Analysis of MP in cream samples showed recovery percentages between 83% and 106%. Advantages of this sensor are the possibility for the determination of higher concentrations of MP when compared with most other reported sensors for MP. The CNC-rGO nanocomposite-based sensor also depicted good reproducibility and reusability compared to the rGO-based sensor. Furthermore, the CNC-rGO nanocomposite sensor showed good selectivity toward MP with little interference from easily oxidizable species such as ascorbic acid.
一种新型的纤维素纳米晶体-还原氧化石墨烯（CNC-rGO）纳米复合材料成功用于对羟基苯甲酸甲酯（MP）的无媒介电化学传感。傅里叶变换红外光谱（FTIR）和场发射扫描电子显微镜（FESEM）研究证实了CNC-rGO纳米复合材料的形成。该纳米复合材料的循环伏安法（CV）研究显示出准可逆的氧化还原行为。采用差分脉冲伏安法（DPV）对传感器进行优化。在优化条件下，该传感器在2×10⁻⁹×10 M范围内呈现线性校准曲线，检测限（LOD）为1×10 M。MP传感器具有良好的重现性，相对标准偏差（RSD）约为8.20%。该传感器对MP测定还表现出良好的稳定性和可重复性。乳膏样品中MP的分析显示回收率在83%至106%之间。与大多数其他报道的MP传感器相比，该传感器的优势在于能够测定更高浓度的MP。与基于rGO的传感器相比，基于CNC-rGO纳米复合材料的传感器还具有良好的重现性和可重复使用性。此外，CNC-rGO纳米复合材料传感器对MP表现出良好的选择性，抗坏血酸等易氧化物质的干扰很小。
