pH计里的玻璃电极是怎么测酸碱度的？
How does a glass electrode in a pH meter measure acidity?
玻璃膜两侧氢离子浓度不同会产生电势差，配合参比电极测出电压，再按能斯特关系换算成pH值。
A thin glass membrane develops a voltage from the H+ concentration difference across it; with a reference electrode this voltage is converted to pH via the Nernst relation.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
武汉大学 主编,《分析化学》第6版,高等教育出版社
Wuhan University eds., Analytical Chemistry, 6th ed., Higher Education Press
#pH计 #玻璃电极 #电势
阳极溶出伏安法为什么能把水中痕量镉、铅测到亚微克每升的水平？
Why can anodic stripping voltammetry determine trace cadmium and lead in water down to sub-microgram-per-litre levels?
它先在负电位下把溶液中的金属离子电解沉积到电极表面的汞（或铋）膜里，相当于把大体积样品中的金属浓缩成一层薄合金，几分钟即可富集上千倍；随后电位向正向扫描，各金属在各自特征电位先后溶出，形成尖窄的峰，峰电流与原始浓度成正比。先电化学预富集、再快速溶出检测，使信噪比大幅提升，检出限因此可达亚ppb级，适合现场水质监测。
At a negative deposition potential the metal ions are electrolytically plated into a thin mercury (or bismuth) film on the electrode, concentrating metal from a large sample volume into a tiny surface layer - often a thousand-fold enrichment within minutes. The potential is then scanned positively, and each metal strips out of the electrode at its own characteristic potential, giving a sharp peak whose current is proportional to the original concentration. Depositing first and detecting afterwards greatly raises the signal-to-noise ratio, pushing detection limits to sub-ppb levels suited to on-site water testing.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-10-04
来源 · Source
A. J. Bard 与 L. R. Faulkner《Electrochemical Methods: Fundamentals and Applications》第2版，Wiley，2001
A. J. Bard & L. R. Faulkner, Electrochemical Methods: Fundamentals and Applications, 2nd ed., Wiley, 2001
独立核验依据 · Independent verification: 核验依据 1 ISBN 978-0-471-04372-0 (2000, Wiley)
#溶出伏安法 #痕量金属 #电化学预富集
第二代安培型葡萄糖传感器为什么要借助二茂铁这类媒介体传递电子，而不沿用葡萄糖氧化酶天然的氧气受体路径？
Why do second-generation amperometric glucose sensors shuttle electrons through mediators such as ferrocene instead of following the enzyme's natural oxygen-acceptor pathway?
为摆脱对溶解氧的依赖，并把工作电位压进干扰物质不再氧化的窗口。机理：天然路径中酶把O₂还原为H₂O₂，电流随生理氧分压起伏，且H₂O₂需在约+0.6 V氧化检测，该电位下抗坏血酸、尿酸、对乙酰氨基酚同步放电造成正偏差；二茂铁衍生物体积小，可贴近黄素活性中心从FADH₂夺取电子，再扩散至电极表面于约+0.2 V再生，信号不再受氧分压牵制，选择性与灵敏度大幅提高。
Mediators free the sensor from dissolved-oxygen dependence and push the operating potential into a window where interferents stay silent. On the natural route the enzyme reduces O2 to H2O2, so the current tracks physiological oxygen tension, and reading the peroxide demands about +0.6 V, where ascorbate, urate, and acetaminophen oxidize side by side and bias results upward. Compact ferrocene derivatives reach the flavin center closely enough to strip electrons from FADH2, then diffuse to the electrode and regenerate near +0.2 V; the signal no longer rides on oxygen, lifting both selectivity and sensitivity.
难度 专业 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
A. E. G. Cass、G. Davis、H. A. O. Hill、A. P. F. Turner等《Ferrocene-mediated enzyme electrode for amperometric determination of glucose》，Analytical Chemistry，1984年，第56卷，667页
A. E. G. Cass et al., Anal. Chem., 1984, 56, 667 (DOI: 10.1021/ac00268a018)
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1021/ac00268a018：Ferrocene-mediated enzym
#电子媒介体 #葡萄糖氧化酶 #安培检测
呼气酒精检测仪是怎么工作的？
How does a breathalyzer work?
呼出气中的乙醇在燃料电池或化学传感器上被氧化，产生的电流与酒精量成正比，从而读出血液酒精浓度。
Ethanol in breath is oxidized at a fuel-cell or chemical sensor; the current produced is proportional to the alcohol amount, estimating blood alcohol.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
武汉大学 主编,《分析化学》第6版,高等教育出版社
Wuhan University eds., Analytical Chemistry, 6th ed., Higher Education Press
#酒精检测 #燃料电池 #氧化
一氧化碳报警器靠什么发现无色无味的CO？
How does a CO alarm detect colorless, odorless carbon monoxide?
传感器(如电化学或金属氧化物型)对CO有选择性反应并产生电信号，浓度超标即报警，弥补了人闻不到的缺陷。
An electrochemical or metal-oxide sensor reacts selectively to CO and generates a signal; it alarms above safe levels, compensating for our inability to smell CO.
难度 进阶 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
武汉大学 主编,《分析化学》第6版,高等教育出版社
Wuhan University eds., Analytical Chemistry, 6th ed., Higher Education Press
#一氧化碳 #传感器 #报警
家用血糖试纸如何把一滴血中的葡萄糖浓度变成电流信号？请说明酶促反应与电极测量之间的衔接原理。
How does a home blood-glucose test strip turn the glucose concentration in a drop of blood into an electrical current? Explain how the enzymatic reaction is coupled to the electrode measurement.
试纸反应区固定着葡萄糖氧化酶：血样中的葡萄糖被催化氧化为葡萄糖酸内酯，酶辅基FAD随之被还原，随后由预置的媒介体铁氰化钾将其重新氧化，自身转变为亚铁氰根。电极间施加恒定电位，亚铁氰根在工作电极上放电产生电流，其大小与葡萄糖浓度成正比。毛细作用吸血，数秒即可完成测定。
The reaction zone of the strip carries immobilized glucose oxidase: glucose in the blood sample is oxidized to gluconolactone, reducing the enzyme's FAD cofactor, which a preloaded mediator, potassium ferricyanide, then reoxidizes while itself becoming ferrocyanide. With a fixed potential applied across the electrodes, ferrocyanide discharges at the working electrode and the resulting current is proportional to the glucose concentration. Capillary action draws in the blood, and the reading is ready within seconds.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
J. Wang, Electrochemical Glucose Biosensors, Chemical Reviews, 2008, 108, 814–825。
J. Wang, Electrochemical Glucose Biosensors, Chem. Rev., 2008, 108, 814–825, DOI: 10.1021/cr068123a.
独立核验依据 · Independent verification: 核验依据 1 CROSSREF 标识 10.1021/cr068123a：Electrochemical Glucose Bi
#电分析 #生物传感器 #葡萄糖氧化酶 #安培法
血糖仪是怎么知道血糖高低的？
How does a blood glucose meter know your sugar level?
试纸上葡萄糖氧化酶把血糖氧化，产生的电子经电极变成电流，电流大小对应血糖浓度，几秒出结果。
Glucose oxidase on the strip oxidizes blood sugar; the resulting electrons become an electric current whose size maps to glucose concentration, read in seconds.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
武汉大学 主编,《分析化学》第6版,高等教育出版社
Wuhan University eds., Analytical Chemistry, 6th ed., Higher Education Press
#血糖仪 #酶电极 #检测