传感器类型
电化学生物传感器
检测对象
多酚指数(polyphenol index,以没食子酸 gallic acid 计);样品基质:葡萄酒(白葡萄酒、红葡萄酒,缓冲液稀释)
检测原理
该传感器以碳纳米管丝网印刷电极为换能器,PAP将漆酶固定于电极表面。葡萄酒中的多酚或标准没食子酸进入流动池后,在漆酶催化下发生氧化,溶解氧作为电子受体被还原为水,电子经碳纳米管导电网络传递至工作电极。在−100 mV(vs Ag/AgCl)恒电位下,氧化还原过程产生与底物浓度相关的阴极安培电流。漆酶催化反应遵循Michaelis–Menten/Hill动力学,电流随多酚浓度增加而增大,从而实现多酚指数的定量测定。
检测灵敏度
LOD: 0.1 mg L−1 (TvL-MWCNTs-SPE);LOD: 0.3 mg L−1 (ThL-MWCNTs-SPE);LOD: 0.6 mg L−1 (ThL-SWCNTs-SPE);线性范围: 0.1–17.0 mg L−1 (TvL-MWCNTs-SPE);线性范围: 0.1–18.0 mg L−1 (ThL-MWCNTs-SPE);灵敏度斜率: 0.009±0.001 μA mg−1 L (TvL-MWCNTs-SPE);灵敏度斜率: 0.007±0.001 μA mg−1 L (ThL-MWCNTs-SPE);灵敏度斜率: 0.004±0.001 μA mg−1 L (ThL-SWCNTs-SPE);R^2 = 0.999 (TvL-MWCNTs-SPE, ThL-MWCNTs-SPE)
效应效果
该传感器对二氧化硫和还原糖无干扰;抗坏血酸对MWCNTs传感器干扰为白葡萄酒8–10%、红葡萄酒5–7%,SWCNTs传感器不受影响。重复性约3–4%,连续6次测量无明显损失,寿命超过10天,单样品分析约4 min。与Folin–Ciocalteau法相比,ThL-MWCNTs回收率92–109%,误差低于8%;ThL-SWCNTs回收率89–96%,较参考法低4–11%(白葡萄酒)和4–8%(红葡萄酒)。作者认为其制备简单、快速、低成本,适合实际葡萄酒多酚监测。
传感器的构成
- 基底/换能器电极:碳纳米管丝网印刷电极(MWCNTs-SPE/SWCNTs-SPE),含碳对电极和Ag/AgCl参比电极,提供电化学换能
- 电极预处理层:0.5 mol/L HNO3处理工作电极,引入羧基功能化,增强固定与电子传递
- 纳米材料修饰层:多壁碳纳米管(MWCNTs)或单壁碳纳米管(SWCNTs),提供导电网络、高比表面积和反应位点
- 识别/催化元件:漆酶(Laccase,TvL或ThL),催化多酚/没食子酸氧化
- 固定化修饰层:聚氮杂环丁烷预聚物(PAP),通过化学交联和物理包埋固定酶
- 检测介质:0.1 mol/L Britton–Robinson缓冲液(pH 5),流动注射载液,维持酶活性与电化学环境
中文摘要
本研究开发并表征了基于 Trametes versicolor(TvL)和 Trametes hirsuta(ThL)漆酶的电化学生物传感器,用于测定葡萄酒中的多酚指数。以聚氮杂环丁烷预聚物(PAP)作为固定化剂,将漆酶固定于多壁碳纳米管(MWCNTs)和单壁碳纳米管(SWCNTs)丝网印刷电极上,分别构建 MWCNTs-SPE 和 SWCNTs-SPE 传感器。以没食子酸为标准底物,在 0.1 mol/L Britton–Robinson 缓冲液(pH 5)流动系统中,于 −100 mV(vs Ag/AgCl)进行安培检测。将结果与 Folin–Ciocalteau 参考方法比较,并对十二种意大利葡萄酒进行分析。结果表明,ThL-MWCNTs 生物传感器更适合葡萄酒多酚指数测定,对没食子酸具有快速可靠的安培响应,线性范围为 0.1–18.0 mg/L(r2=0.999),并系统评估了干扰物质对光谱法和电化学法的影响。
英文摘要
In this work we have developed and characterized the use of Laccases from Trametes versicolor (TvL) and Trametes hirsuta (ThL) as biocatalytic components of electrochemical biosensors for the determination of polyphenol index in wines. Polyazetidine prepolimer (PAP) was used as immobilizing agent, multi-walled and single-walled carbon nanotubes screen-printed electrodes as sensors (MWCNTs-SPE and SWCNTs-SPE) and gallic acid as standard substrate. The amperometric measurements were carried out by using a flow system at a fixed potential of -100 mV vs. silver/silver chloride electrode in Britton-Robinson buffer 0.1 mol L(-1), pH 5. The results were compared with those obtained with the Folin-Ciocalteau reference method. The results obtained in the analysis of twelve Italian wines put in evidence the better suitability of ThL-MWCNTs-based biosensor in the determination of the polyphenol index in wines. This biosensor shows fast and reliable amperometric responses to gallic acid with a linear range 0.1-18.0 mg L(-1) (r(2)=0.999). The influence of the interferences on both spectrophotometric and electrochemical measurements have been carefully evaluated.