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Electrochemical sensors: precision chemistry that sees the invisible
Electrochemical sensors have become an integral part of modern medicine, ecology, the food industry, and even security. They allow you to detect the smallest concentrations of substances in biological fluids, air, or water — quickly, accurately, and without complex laboratory procedures.
What is an electrochemical sensor?
This is a device that converts chemical information (presence, concentration of a certain substance) into an electrical signal. It is based on electrode(s) that interact with the analyte (the substance being tested) and respond by changing current, voltage, or impedance.
Electrochemical sensor components:
Working electrode — where the reaction takes place;
Reference electrode — ensures stability of potential;
Auxiliary electrode — closing of an electrical circuit;
Membrane/bioselective layer — is responsible for specificity (for example, an enzyme, antibody, or artificial receptor structure).
Types of electrochemical sensors
| Sensor type | Principle of operation | Application example |
|---|---|---|
| Amperometric | Measures the current resulting from the oxidation/reduction of the analyte | Glucometers |
| Potentiometric | Measures changes in electrical potential | Ion-selective electrodes (e.g. pH meters) |
| Conductometric | Measures changes in the electrical conductivity of the medium | Determination of salts in water |
| Impedance | Analyzes the resistance and capacitance of an electrical circuit | Diagnosis of cellular changes, biosensors |
Where are electrochemical sensors used?
Medicine
glucometers for blood sugar control;
sensors on lactate, cholesterol, creatinine;
cancer markers in saliva or plasma.
Ecology
detection of heavy metals in rivers and soils;
air pollution control (ozone, hydrogen sulfide, NO₂).
Agro-industry
control of nitrates in products;
detection of pesticides in soil or vegetables;
measuring the ionic composition of the soil solution.
Food industry
quality control of dairy products;
detection of counterfeits and expired goods.
Security and military affairs
detection of toxins, poisons, explosives;
saliva/breath alcohol or drug testing.
Advantages of electrochemical sensors
High sensitivity — determination of even nano- and pico-concentrations;
Speed — results within minutes or even seconds;
Miniaturization — the possibility of creating portable or wearable devices;
Cost — cheaper than many spectroscopic or chromatographic methods;
Possibility of integration with electronics — connection to a smartphone, monitoring automation.
Modern research and innovation
Leading laboratories around the world are actively researching:
Nanostructured electrodes — use of carbon nanotubes, graphene, gold nanoparticles;
DNA-based biosensors — to detect mutations or viral fragments;
Paper sensors — disposable, cheap, biodegradable;
Integration with the Internet of Things (IoT) — sensors that transmit data online in real time.
Example: How does a blood glucose meter work?
A drop of blood is applied to the test strip.
The enzyme (glucose oxidase) reacts with glucose → hydrogen peroxide is formed.
This product is oxidized at the electrode → an electric current is generated.
The current strength is proportional to the concentration glucose.
The result is displayed on the screen.
Electrochemical sensors are universal chemical “detectives” of a new generation. They already determine the composition of blood, the quality of water and products on store shelves. Every year they become more accurate, smaller and smarter. And most importantly, closer to a person: in a pocket, on a wrist or in a smartphone.
