Definition of chemical sensing

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Photonics Dictionary

chemical sensing: Chemical sensing refers to the detection and measurement of specific chemical compounds or substances in various environments or samples. It involves the use of sensors or analytical techniques to detect, identify, and quantify the presence of target molecules based on their chemical properties. Chemical sensing plays a crucial role in a wide range of fields, including environmental monitoring, industrial process control, biomedical diagnostics, food safety, and security.

Principles of operation:

Chemical reactions: Sensors that rely on chemical reactions between the target analyte and a sensing material, leading to a change in a measurable property such as color, conductivity, or pH.

Optical absorption/emission: Sensors that utilize the absorption or emission of light by the target analyte to measure its concentration or presence.

Mass change: Sensors that detect changes in mass or weight due to the adsorption or absorption of the target analyte onto a sensing surface.

Electrochemical processes: Sensors that measure changes in electrical properties (e.g., voltage, current) resulting from electrochemical reactions between the target analyte and an electrode.

Types of chemical sensors:

Gas sensors: Detect and measure the concentration of gases in the atmosphere or within enclosed spaces. Common applications include air quality monitoring, industrial safety, and detection of toxic or flammable gases.

Biosensors: Specifically designed to detect biomolecules, such as proteins, enzymes, DNA, or antibodies. They are widely used in medical diagnostics, environmental monitoring, and food safety.

Ion-selective electrodes: Designed to measure the concentration of specific ions (e.g., pH sensors, ion-selective electrodes for measuring ions such as sodium, potassium, chloride) in aqueous solutions.

Surface plasmon resonance (SPR) sensors: Based on the interaction between surface plasmons and target analytes adsorbed onto a metal surface, commonly used in biochemistry and drug discovery.

Chemical imaging: Techniques that combine chemical sensing with imaging capabilities to provide spatially resolved chemical information about samples, such as Raman spectroscopy, infrared spectroscopy, and mass spectrometry imaging.

Applications:

Environmental monitoring: Detection of pollutants, gases, and contaminants in air, water, and soil to assess environmental quality and health risks.

Healthcare and biomedical diagnostics: Diagnosis and monitoring of diseases, detection of biomarkers, drug discovery, and personalized medicine.

Industrial process control: Monitoring and control of chemical processes in manufacturing, refining, and pharmaceutical industries to ensure product quality and safety.

Food and beverage industry: Quality control, safety testing, and authentication of food products to detect contaminants, adulterants, or spoilage.

Security and defense: Detection of explosives, chemical warfare agents, illicit drugs, and hazardous materials for homeland security and military applications.

Challenges and advances: Challenges in chemical sensing include improving sensitivity, selectivity, reliability, and miniaturization of sensors for portable and wearable applications. Recent advances in nanotechnology, materials science, microfabrication, and machine learning have led to the development of more sensitive, selective, and versatile chemical sensing platforms with enhanced performance and functionality.

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