Gas Detection Using Portable Deep-UV Absorption Spectrophotometry: A Review

Khan, Sulaiman; Newport, David; Calvé, Stéphane Le

doi:10.3390/s19235210

Cited by 50 publications

(32 citation statements)

References 101 publications

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“…However, humidity could absorb into the reflective surface of the HCW and decrease the transmission of UV radiation with time. Nafion membrane at the inlet or quartz lining of the aluminium coating are usually used to avoid the negative effects of humidity on the sensing system [20].…”

Section: Detection Of Btex With µGcmentioning

confidence: 99%

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A Sensitive and Portable Deep-UV Absorbance Detector with a Microliter Gas Cell Compatible with Micro GC

2021

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Deep-UV absorption spectrometry for detection of toxic airborne gases, for instance, Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX) has drawn considerable attention owing to its high sensitivity and reliability. However, the development of a deep-UV absorbance detector having good sensitivity, portability, and a low-volume gas cell with applicability for a micro Gas Chromatography (μGC) is challenging. Herein we present a novel, self-referenced, and portable deep-UV absorbance detector with a microliter (275 μL) gas cell having minimal dead volume. It has excellent compatibility with μGC for detection of individual BTEX components in a mixed sample at a sub-ppm level. The design consists of the latest, portable, and cost-effective optical and electronic components, i.e., deep-UV LED, hollow-core waveguide, and photodiodes. The detector directly measures the absorbance values in volts using an integrated circuit with a log-ratio amplifier. The prototype was tested with direct injection of toluene-N2 (1.5 ppm to 50 ppm) and good linearity (R2 = 0.99) with a limit of detection of 196 ppb was obtained. The absorbance detector with μGC setup was tested with a BTEX mixture in N2 at different GC column temperatures. All the BTEX species were sequentially separated and detected with an individual peak for a concentration range of 2.5 ppm to 10 ppm.

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Section: Detection Of Btex With µGcmentioning

confidence: 99%

“…HCWs transmit UV radiation in a leaky-mode through the reflection of the emitted radiation inside the co-axial hollow core. Aluminium is considered to be an efficient coating material for deep-UV radiation compared to other metals, for instance silver, and it has good chemical compatibility with airborne BTEX molecules [20].…”

Section: Introductionmentioning

confidence: 99%

A Sensitive and Portable Deep-UV Absorbance Detector with a Microliter Gas Cell Compatible with Micro GC

2021

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“…At 600 nm, the abovementioned sensor showed high sensitivity at low O 3 concentrations, and good reproducibility and stability. In addition, a review of deep ultraviolet absorption applied to gas sensing is presented in [ 67 ], and a discussion of applications of ultraviolet absorption spectrometry for O 3 and other air pollutants is given in [ 67 ].…”

Section: Some General Comments On Ozone Sensors: Characteristics Amentioning

confidence: 99%

“…However, it is not enough to design a sensor that measures the value of a certain physical quantity; this measurement must also be as robust as possible against disturbances and unwanted information. In this sense, several authors [ 66 , 67 ] are also concerned about the robustness that the sensors could have and are aware of the limitations of the sensor as an isolated element. Therefore, to achieve a good design of measurement equipment, it is necessary to put the sensor inside a signal conditioning and processing system that is capable of dealing with everything that represents noise, disturbance, and unwanted information [ 73 ].…”

Section: Some General Comments On Ozone Sensors: Characteristics Amentioning

confidence: 99%

Robust Inferential Techniques Applied to the Analysis of the Tropospheric Ozone Concentration in an Urban Area

Hernández

Méndez

González-Posadas

et al. 2021

Sensors

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This paper analyzes 12 years of tropospheric ozone (O3) concentration measurements using robust techniques. The measurements were taken at an air quality monitoring station called Belisario, which is in Quito, Ecuador; the data collection time period was 1 January 2008 to 31 December 2019, and the measurements were carried out using photometric O3 analyzers. Here, the measurement results were used to build variables that represented hours, days, months, and years, and were then classified and categorized. The index of air quality (IAQ) of the city was used to make the classifications, and robust and nonrobust confidence intervals were used to make the categorizations. Furthermore, robust analysis methods were compared with classical methods, nonparametric methods, and bootstrap-based methods. The results showed that the analysis using robust methods is better than the analysis using nonrobust methods, which are not immune to the influence of extreme observations. Using all of the aforementioned methods, confidence intervals were used to both establish and quantify differences between categories of the groups of variables under study. In addition, the central tendency and variability of the O3 concentration at Belisario station were exhaustively analyzed, concluding that said concentration was stable for years, highly variable for months and hours, and slightly changing between the days of the week. Additionally, according to the criteria established by the IAQ, it was shown that in Quito, the O3 concentration levels during the study period were not harmful to human health.

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“…The incident beam can be produced from a variety of sources including lasers, light-emitting diodes, tungsten-halogen bulbs, and arc lamps (containing mercury, xenon, or deuterium). These light sources have their own advantages and disadvantages, and the intended use of the detector dictates which source can be used [2]. LIF spectroscopy offers several advantages over absorption spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Current State of Laser-Induced Fluorescence Spectroscopy for Designing Biochemical Sensors

Taylor

Lai

2021

Chemosensors

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Laser-induced fluorescence (LIF) has been a valuable analytical technique since the 1970s that has only been made more useful through advances in other scientific fields such as biochemistry. Moreover, advances in laser and detector technology have seen a decrease in LIF detector costs and an increase in their ease of use. These changes have allowed for LIF technology to be widely adopted for various sensor designs in combination with advanced instruments. With advances in biochemistry necessitating the detection of complex metabolites, labelling with fluorescent chemical reagents may be necessary to improve detection sensitivity. Furthermore, advances made in fluorescent labeling technologies have allowed for the use of LIF in the detection of nanoparticles as well as for imaging techniques using nanoparticles as signal amplifiers. This technology has become invaluable in the detection of environmental pollutants, monitoring of biological metabolites, biological imaging, and cancer diagnosis, making it one of the most valuable analytical science techniques currently available.

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Gas Detection Using Portable Deep-UV Absorption Spectrophotometry: A Review

Cited by 50 publications

References 101 publications

A Sensitive and Portable Deep-UV Absorbance Detector with a Microliter Gas Cell Compatible with Micro GC

A Sensitive and Portable Deep-UV Absorbance Detector with a Microliter Gas Cell Compatible with Micro GC

Robust Inferential Techniques Applied to the Analysis of the Tropospheric Ozone Concentration in an Urban Area

Current State of Laser-Induced Fluorescence Spectroscopy for Designing Biochemical Sensors

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