CM211IA UNIT 4 SENSORS ELECTROCHEMICAL SENSOR

Описание: In this lecture, we discuss the fundamentals of Electrochemical Sensors, a key topic under Unit 4: Sensors of the CM211IA Engineering Chemistry syllabus.

Sensors play a crucial role in converting physical or chemical signals into measurable electrical outputs. Among them, electrochemical (EC) sensors are widely used due to their high sensitivity, low power consumption, and portability.

🔬 Topics Covered in This Lecture:

Basic concept of sensors and signal transduction
Principle of electrochemical sensors based on redox reactions
Types of electrical signals measured:
Current
Voltage
(Primarily amperometric sensing)

Electrode system in EC sensors:
Working Electrode (WE): site of analyte oxidation/reduction
Counter Electrode (CE): completes the electrical circuit
Reference Electrode (RE): maintains stable potential
Screen-Printed Electrodes (SPEs):
Compact
Disposable
Suitable for portable sensing applications

⚙️ Construction and Working Mechanism:
Diffusion of analyte towards the working electrode
Oxidation/reduction reaction at the electrode surface
Generation of electron flow
Electrical signal proportional to analyte concentration

🧪 Materials Used in Electrochemical Sensors:
Noble metals: Pt, Au, Ag
Carbon-based materials
Metal oxides
Enzymes (for biosensors)

🧬 Examples of Electrochemical Sensors:
Biosensors: Glucose, ascorbic acid
Gas and VOC sensors: CO, NOₓ, H₂S, LPG

✅ Advantages:
High sensitivity and selectivity
Low power requirement
Portable and miniaturized devices

⚠️ Limitations:
Signal interference
Electrode fouling
Limited operational lifetime

🌍 Applications:
Healthcare and medical diagnostics
Environmental monitoring
Industrial safety and gas detection

📌 This lecture is useful for:
B.E / B.Tech students (Chemistry, ECE, EEE, AI & ML, Mechanical), competitive exams, and beginners in sensor technology.

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