Electrochemical Gas Sensors

Opekar, František; Štulı́k, Karel

doi:10.1002/9780470027318.a9074

Cited by 5 publications

(5 citation statements)

References 30 publications

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“…Concentrations as low as 500 ppm can be lethal, and the current (USA) Occupational Safety and Health Administration Permissible Exposure Limit (OSHA PEL) for NH 3 is 25 ppm in the gas phase. Although a range of different strategies can been employed to monitor toxic gases, , electrochemical gas sensors are popular due to their low cost, portability, low power consumption, high sensitivity, and selectivity and ability to be miniaturized. , Commercially available amperometric gas sensors (AGSs) for ammonia are sold by a range of companies, but a major drawback is that the solvent/electrolyte combination (typically water/sulfuric acid) can dry up (particularly in hot and dry environments) and decrease the sensor lifetime. As a result, nonvolatile room temperature ionic liquids (RTILs) have been attracting attention − as replacement electrolytes in “membrane-free” AGSs.…”

mentioning

confidence: 99%

Detection of sub-ppm Concentrations of Ammonia in an Ionic Liquid: Enhanced Current Density Using “Filled” Recessed Microarrays

Hussain

Silvester

2016

Anal. Chem.

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The voltammetric detection of less than 1 ppm of ammonia gas in the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Cmim][NTf]) is demonstrated using low-cost planar electrode devices. Three commercially available planar devices were employed, all with platinum (Pt) working electrodes: a thin-film electrode (TFE), a screen-printed electrode (SPE), and a microarray thin film electrode (MATFE), along with an "ideal" conventional Pt microdisk electrode for comparison. The microholes on the recessed MATFE were also "filled" with electrodeposited platinum, to improve radial diffusion characteristics to the microhole and generate higher current densities. Current density was lowest for the TFE and SPE surfaces (linear diffusion), higher for the MATFE (mixed radial and linear diffusion), and even higher for the filled MATFE (predominantly radial diffusion). Linear sweep voltammetry (LSV) and potential-step chronoamperometry (PSCA) at 10-100 ppm of NH gave linear behavior for current vs concentration. Limits of detection (LODs) were in the range of ca. 1-9 ppm, lower than the minimum exposure limit (25 ppm) for NH. The best stability, reproducibility, and the lowest LODs were observed on the recessed and filled MATFEs. These were employed to detect lower concentrations of ammonia (0.1-2 ppm), where linear behavior was also observed, and LODs of 0.11 (recessed) and 0.02 (filled) were obtained. These are believed to be the lowest LODs (to date) reported for ammonia gas in neat ionic liquids. This is highly encouraging and suggests that RTILs and low-cost miniaturized MATFEs can be combined in amperometric sensor devices to easily and cheaply detect ammonia gas at ppb concentrations.

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confidence: 99%

Detection of sub-ppm Concentrations of Ammonia in an Ionic Liquid: Enhanced Current Density Using “Filled” Recessed Microarrays

Hussain

Silvester

2016

Anal. Chem.

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“…Conductometric sensors measures the change in resistance or the conductivity of electrolyte, while a constant alternatingcurrent (AC) potential is maintained between the two electrodes. Amperometric and potentiometric sensors are mostly used for the detection of toxic chemicals, while coulometric and conductometric sensors are rarely applied [46][47][48]. The working mechanism of a simple electrochemical sensor was shown in figure 6.1.…”

Section: Working Mechanismmentioning

confidence: 99%

Graphene-Metal Chalcogenide based Electrochemical Sensors for Toxic Chemicals

Arivarasan

2020

Graphene-Based Electrochemical Sensors for Toxic Chemicals

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The developments in industrial and technological sectors result in severe environmental issues, such as environmental contamination and pollution. Among the various types of contaminations, toxic gases, heavy metal ions, pesticides and fertilizers, etc., play a major role in environmental issues. As an advancement of the sensors used to detect such toxic chemicals, electrochemical sensor attracts much attention in recent days. The development of graphene based nanocomposites for electrochemical sensors, paving a new path for the sensitive and efficient detection of such chemicals. Graphene/metal chalcogenide based nanocomposites have gained worldwide attention in recent decades and are being researched for use in different applications due to their unique physical and chemical properties. This chapter aims a comprehensive presentation of various toxic chemicals, their environmental effects and their conventional sensing mechanism. The role of graphene, metal chalcogenides and their nanocomposites on the sensing mechanism in electrochemical sensors were reviewed.

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“…Notwithstanding their efficacy, these methods tend to be slow, demand proficient personnel, and entail analysis in a laboratory setting, thereby rendering them less appropriate for expeditious on-site monitoring. Lately, to address these issues, various sensor types, including, but not limited to, electrochemical 14 and solid-state, 15 have been developed. These sensors offer improved detection sensitivity, selectivity, speed, portability, and ease of use.…”

Section: Introductionmentioning

confidence: 99%

Highly selective and sensitive detection of volatile organic compounds using long wavelength InAs-based quantum cascade lasers through quartz-enhanced photoacoustic spectroscopy

Kinjalk,

Paciolla,

Sun

et al. 2024

Applied Physics Reviews

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The precise detection of volatile organic compounds plays a pivotal role in addressing environmental concerns, industrial safety, and medical diagnostics. The accurate identification and quantification of these compounds because of their ubiquity and potential health hazards has fueled the development of advanced sensing technologies. This work presents a sensing system in the realm of long-wavelength infrared spectroscopy for achieving enhanced selectivity and sensitivity of benzene, toluene, and propane detection through quartz-enhanced photoacoustic spectroscopy. High-resolution gas spectroscopy is made possible by the use of specially designed InAs/AlSb-based quantum cascade lasers, emitting in the wavelength range 13–15 μm, and quartz tuning forks. The sensor system, characterized by its robustness and precision, demonstrates exceptional capabilities in benzene, toluene, and propane detection. The system's capacity for practical applications in environmental monitoring and medical diagnostics is demonstrated by its ability to distinguish these volatile organic compounds with a minimum detection limit of 113 ppb, 3 ppb, and 3 ppm for toluene, benzene, and propane at an integration time of 10 s, even in complex gas matrices. This work advances gas sensing technology while also offering insightful information on spectral interferences, a persistent problem in the field. The results usher in a new era of sophisticated and reliable gas sensing techniques meeting the growing demand for precise volatile organic compounds detectors for environmental monitoring purposes.

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Electrochemical Gas Sensors

Cited by 5 publications

References 30 publications

Detection of sub-ppm Concentrations of Ammonia in an Ionic Liquid: Enhanced Current Density Using “Filled” Recessed Microarrays

Detection of sub-ppm Concentrations of Ammonia in an Ionic Liquid: Enhanced Current Density Using “Filled” Recessed Microarrays

Graphene-Metal Chalcogenide based Electrochemical Sensors for Toxic Chemicals

Highly selective and sensitive detection of volatile organic compounds using long wavelength InAs-based quantum cascade lasers through quartz-enhanced photoacoustic spectroscopy

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