组成图示
示意图生成中
传感器类型
电化学生物传感器
检测对象
乙醇（ethanol, EtOH）；样品基质：啤酒（beer）及磷酸盐缓冲液标准溶液
检测原理
传感器以 Clark 型溶解氧（DO）探针为换能器，聚四氟乙烯膜允许氧选择性透过。固定化过氧化氢酶（catalase）先催化 H2O2 分解：2H2O2 → 2H2O + O2，使膜界面 DO 浓度升高并形成初始稳态。加入乙醇后，catalase 同时催化 H2O2 分解和乙醇氧化：CH3CH2OH + H2O2 → CH3CHO + 2H2O。由于 H2O2 被乙醇反应竞争消耗，产氧速率下降，DO 稳态降低。初始稳态与最终稳态的 DO 浓度差与乙醇浓度成正比，由 DO 探针以安培/氧电导信号读出。该设计利用 H2O2 作为辅助底物放大乙醇引起的 DO 变化，无需外加电子供体。
检测灵敏度
LOD: 0.05 mM；线性范围: 0.05–1.0 mM；R^2 = 0.9996；线性方程: y = 0.305 + 0.032（原文摘录）；响应时间: 3 min
效应效果
传感器对乙醇选择性较好：0.4 mM 乙醇响应为100%，甲醇、正丙醇、正丁醇、异丙醇、葡萄糖响应分别为17%、50%、29%、25%、17%，乙二醇和二乙二醇无响应。重现性良好，0.4 mM 乙醇 n=10，平均 0.396±0.00516 mM，CV 1.30%。储存6周后保留活性>78%，可完成>50次测量。啤酒样品（标称3.0、4.0、5.0%）稀释后测定，传感器结果为2.96±0.00223、3.95±0.00230、4.97±0.00370%，CV 1.10%、1.14%、1.84%；酶法比色法为3.13±0.0618、4.11±0.0980、5.19±0.0983%，CV 1.97%、2.01%、1.92%。作者认为其灵敏度和精密度优于比色法，成本低，适合常规乙醇分析。
传感器的构成
- 换能器基底：Clark 型溶解氧（DO）探针（YSI 5739），用于检测膜界面溶解氧浓度
- 选择性膜：高灵敏度聚四氟乙烯（teflon）膜（0.0005 in.），以 O-ring 固定，允许氧选择性透过
- 膜表面预处理：0.5% SDS 磷酸盐缓冲液（50 mM, pH 7.5）处理 teflon 膜，降低表面张力
- 识别/催化元件：过氧化氢酶（catalase, E.C 1.11.1.6），催化 H2O2 分解和乙醇氧化
- 固定化基质：明胶（gelatin, calf skin, 225 bloom），与 catalase 混合形成生物活性层
- 交联固定层：戊二醛（glutaraldehyde, 2.5%）交联 gelatin-catalase 层，提高稳定性
中文摘要
本研究开发了一种基于过氧化氢酶（catalase）的安培型生物传感器，用于啤酒样品中乙醇的测定。传感器以覆盖聚四氟乙烯（teflon）膜的 Clark 型溶解氧（DO）探针为换能器，利用明胶（gelatin）和戊二醛（glutaraldehyde）将过氧化氢酶固定于膜表面。其工作原理基于过氧化氢酶催化的两个相互关联反应：首先，过氧化氢酶催化过氧化氢（H2O2）分解生成氧气，使膜界面溶解氧浓度达到初始稳态；随后加入乙醇时，酶同时催化 H2O2 分解和乙醇氧化为乙醛，H2O2 被竞争消耗，导致溶解氧稳态下降。初始与最终稳态 DO 浓度之差与乙醇浓度相关，由 DO 探针检测。传感器在 0.05–1.0 mM 乙醇范围内呈线性响应，检出限为 0.05 mM，响应时间约 3 min。优化条件为 50 mM 磷酸盐缓冲液（pH 7.0）和 35 °C。研究还考察了重现性、底物特异性、操作与储存稳定性，并将该传感器与酶法比色法用于啤酒样品乙醇测定，结果显示其灵敏度和精密度优于比色法，适合常规乙醇分析。
英文摘要
An amperometric biosensor based on catalase enzyme for alcohol determination was developed. To construct the biosensor catalase was immobilized by using gelatin and glutaraldehyde on a Clark type dissolved oxygen (DO) probe covered with a teflon membrane which is sensitive for oxygen. The working principle of the biosensor depends on two reactions, which one is related to another, catalyzed by catalase enzyme. In the first reaction catalase catalyzes the degradation of hydrogen peroxide and oxygen is produced and also a steady-state DO concentration occurs in a few minutes. When ethanol added to the medium catalase catalyzes the degradation of both hydrogen peroxide and ethanol and this results in a new steady-state DO concentration. Difference for first and the last steady-state DO concentration occurred in the interval surface of DO probe membrane, which related to ethanol concentration, are detected by the biosensor. The biosensor response depends linearly on ethanol concentration between 0.05 and 1.0 mM with a detection limit of 0.05 mM and a response time of 3 min. In the optimization studies of the biosensor phosphate buffer (pH 7.0; 50 mM) and 35 degrees C were established as providing the optimum working conditions. In the characterization studies of the biosensor some parameters such as reproducibility, substrate specificity, operational and storage stability were carried out. Finally, by using the biosensor developed and enzimatic-spectrophotometric method alcohol concentration of some alcoholic drinks were determined and results were compared.