Chemical sensor
A chemical sensor is a device that transforms chemical information (composition, presence of a particular element or ion, concentration, chemical activity, partial pressure…) into an analytically useful signal.
The chemical information, mentioned above, may originate from a chemical reaction of the analyte or from a physical property of the system investigated. They can have applications in different areas such as medicine, home safety, environmental pollution and many others.
Types of Chemical sensor
| Sl.No | Chemical Sensor | Description |
|---|---|---|
| 1 | Breathalyzer | A breathalyzer or breathalyser is a device for estimating blood alcohol content (BAC) from a breath sample. |
| 2 | Carbon dioxide sensor | A carbon dioxide sensor or CO2 sensor is an instrument for the measurement of carbon dioxide gas. The most common principles for CO2 sensors are infrared gas sensors (NDIR) and chemical gas sensors. Measuring carbon dioxide is important in monitoring indoor air quality, the function of the lungs in the form of a capnograph device, and many industrial processes. |
| 3 | Carbon monoxide detector | A carbon monoxide detector or CO detector is a device that detects the presence of the carbon monoxide (CO) gas in order to prevent carbon monoxide poisoning. In the late 1990s Underwriters Laboratories changed their definition of a single station CO detector with a sound device in it to a carbon monoxide (CO) alarm. This applies to all CO safety alarms that meet UL 2034 standard[1]; however for passive indicators and system devices that meet UL 2075, UL refers to these as carbon monoxide detectors. |
| 4 | Catalytic bead sensor | A catalytic bead sensor is a type of sensor that is used for combustible gas detection from the family of gas sensors known as pellistors. |
| 5 | Chemical field-effect transistor | A ChemFET is a chemically-sensitive field-effect transistor, that is a field-effect transistor used as a sensor for measuring chemical concentrations in solution. When the target analyte concentration changes, the current through the transistor will change accordingly. |
| 6 | Chemiresistor | A chemiresistor is a material that changes its electrical resistance in response to changes in the nearby chemical environment. Chemiresistors are a class of chemical sensors that rely on the direct chemical interaction between the sensing material and the analyte. Several different materials have chemiresistor properties: metal-oxide semiconductors, some conductive polymers, and nanomaterials like graphene, carbon nanotubes and nanoparticles. Typically these materials are used as partially selective sensors in devices like electronic tongues or electronic noses. |
| 7 | Electrochemical gas sensor | Electrochemical gas sensors are gas detectors that measure the concentration of a target gas by oxidizing or reducing the target gas at an electrode and measuring the resulting current. |
| 8 | Electronic nose | An electronic nose is a device intended to detect odors or flavors. The expression “electronic sensing” refers to the capability of reproducing human senses using sensor arrays and pattern recognition systems. The stages of the recognition process are similar to human olfaction and are performed for identification, comparison, quantification and other applications, including data storage and retrieval. The stages of the recognition process are similar to human olfaction and are performed for identification, comparison, quantification and other applications, including data storage and retrieval. |
| 9 | Electrolyte–insulator–semiconductor sensor | An Electrolyte–insulator–semiconductor (EIS) sensor is a sensor that is made of these three components: an electrolyte with the chemical that should be measured, an insulator that allows field-effect interaction, without leak currents between the two other components, a semiconductor to register the chemical changes |
| 10 | Energy-dispersive X-ray spectroscopy | It is an analytical technique used for the elemental analysis or chemical characterization of a sample. It relies on an interaction of some source of X-ray excitation and a sample. Its characterization capabilities are due in large part to the fundamental principle that each element has a unique atomic structure allowing a unique set of peaks on its electromagnetic emission spectrum. It is known by many acronyms like EDS, EDX, EDXS or XEDS sometimes called energy dispersive X-ray analysis (EDXA) or energy dispersive X-ray microanalysis (EDXMA) |
| 11 | Fluorescent chloride sensors | Fluorescent chloride sensors are used for chemical analysis. The discoveries of chloride (Cl−) participations in physiological processes stimulates the measurements of intracellular Cl− in live cells and the development of fluorescent tools |
| 12 | Holographic sensor | A holographic sensor is a device that comprises a hologram embedded in a smart material that detects certain molecules or metabolites. This detection is usually a chemical interaction that is transduced as a change in one of the properties of the holographic reflection (as in the Bragg reflector), either refractive index or spacing between the holographic fringes. The specificity of the sensor can be controlled by adding molecules in the polymer film that selectively interacts with the molecules of interest. |
| 13 | Hydrocarbon dew point analyzer | A dew point analyzer measures the amount of moisture present in a gas to determine the theoretical temperature at which the moisture in the gas will condense (the saturation point) |
| 14 | Hydrogen sensor | A hydrogen sensor is a gas detector that detects the presence of hydrogen. They contain micro-fabricated point-contact hydrogen sensors and are used to locate hydrogen leaks. They are considered low-cost, compact, durable, and easy to maintain as compared to conventional gas detecting instruments |
| 15 | Hydrogen sulfide sensor | A hydrogen sulfide sensor or H2S sensor is a gas sensor for the measurement of hydrogen sulphide. It is used to detect hydrogen sulphide in the hydrogen feed stream of fuel cells to prevent catalyst poisoning and to measure the quality of guard beds used to remove sulphur from hydrocarbon fuels. a hydrogen sulphide sensor is used in personal protective equipment to warn for the presence of hydrogen sulphide gas, e.g. on acid gas production sites. |
| 16 | Infrared point sensor | An infrared point sensor is a point gas detector based on the nondispersive infrared sensor technology. Toxic gases are measured in the low parts per million (ppm) range. Flammable gases are measured in the 0 - 100% lower flammable limit (LFL) or lower explosive limit (LEL) range. |
| 17 | Ion-selective electrode | An ion-selective electrode (ISE), also known as a specific ion electrode (SIE), is a transducer that converts the activity of a specific ion dissolved in a solution into an electrical potential. The voltage is theoretically dependent on the logarithm of the ionic activity, according to the Nernst equation. Ion-selective electrodes are used in analytical chemistry and biochemical/biophysical research, where measurements of ionic concentration in an aqueous solution are required. |
| 18 | Nondispersive infrared sensor | A nondispersive infrared sensor (or NDIR sensor) is a simple spectroscopic sensor often used as a gas detector. It is nondispersive in the sense of optical dispersion since the infrared energy is allowed to pass through the atmospheric sampling chamber without deformation. |
| 19 | Microwave chemistry sensor | Microwave chemistry sensor or Surface acoustic wave (SAW) sensors consist of an input transducer, a chemically adsorbent polymer film, and an output transducer on a piezoelectric substrate, which is typically quartz. SAWS have been able to distinguish organophosphates, chlorinated hydrocarbons, ketones, alcohols, aromatic hydrocarbons, saturated hydrocarbons, and water . |
| 20 | Nitrogen oxide sensor | A nitrogen oxide sensor or NOx sensor is typically a high-temperature device built to detect nitrogen oxides in combustion environments such as an automobile or truck tailpipe or a smokestack. |
| 21 | Olfactometer | An olfactometer is an instrument used to detect and measure odor dilution. Olfactometers are used in conjunction with human subjects in laboratory settings, most often in market research, to quantify and qualify human olfaction. Olfactometers are used to gauge the odor detection threshold of substances. To measure intensity, olfactometers introduce an odorous gas as a baseline against which other odors are compared. An olfactometer is also a device used for producing aromas in a precise and controlled manner |
| 22 | Optode | An optode or optrode is an optical sensor device that optically measures a specific substance usually with the aid of a chemical transducer. Optical sensors are growing in popularity due to the low-cost, low power requirements and long term stability. They provide viable alternatives to electrode-based sensors or more complicated analytical instrumentation, especially in the field of environmental monitoring |
| 23 | Oxygen sensor | An oxygen sensor (or lambda sensor, where lambda refers to air–fuel equivalence ratio, usually denoted by λ) is an electronic device that measures the proportion of oxygen (O2) in the gas or liquid being analysed. |
| 24 | Ozone monitor | An ozone monitor is electronic equipment that monitors for ozone concentrations in the air. The instrument may be used to monitor ozone values for industrial applications or to determine the amount of ambient ozone at ground level and determine whether these values violate National Ambient Air Quality Standards (NAAQS). |
| 25 | Pellistor | A pellistor is a solid-state device used to detect gases which are either combustible or which have a significant difference in thermal conductivity to that of air. The word “pellistor” is a combination of pellet and resistor. |
| 26 | pH glass electrode | A glass electrode is a type of ion-selective electrode made of a doped glass membrane that is sensitive to a specific ion. The most common application of ion-selective glass electrodes is for the measurement of pH. The pH electrode is an example of a glass electrode that is sensitive to hydrogen ions. Glass electrodes play an important part in the instrumentation for chemical analysis and physico-chemical studies. The voltage of the glass electrode, relative to some reference value, is sensitive to changes in the activity of certain type of ions. |
| 27 | Potentiometric sensor | A potentiometric sensor is a type of chemical sensor that may be used to determine the analytical concentration of some components of the analyte gas or solution. These sensors measure the electrical potential of an electrode when no voltage is present. |
| 28 | Smoke detector | A smoke detector is a device that senses smoke, typically as an indicator of fire. Commercial security devices issue a signal to a fire alarm control panel as part of a fire alarm system, while household smoke detectors, also known as smoke alarms, generally issue a local audible or visual alarm from the detector itself. |
| 29 | Zinc oxide nanorod sensor | A zinc oxide nanorod sensor or ZnO nanorod sensor is an electronic or optical device detecting presence of certain gas or liquid molecules in the ambient atmosphere. The sensor exploits enhanced surface area (and thus surface activity) intrinsic to all nano-sized materials, including ZnO nanorods. Adsorption of molecules on the nanorods can be detected through variation of the nanorods’ properties, such as photoluminescence, electrical conductivity, vibration frequency, mass, etc. The simplest and thus most popular way is to pass electrical current through the nanorods and observe its changes upon exposure to gas. |