Chemiluminescence is the luminescence produced due to chemical reactions. This powerful analytical technique is used in chemical analyses, especially for qualitative and quantitative analysis of trace gases. This article provides an overview of chemiluminescence gas analysis and its applications.
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Gas Analysis and its Significance
Gas analysis is a crucial separation method widely used in research, development, and industry. This technique is often used to determine the concentration of a gas in the atmosphere or an environment consisting of a mixture of gases.
For instance, in the pharmaceutical industry, gas analysis is used to detect and quantify impurities, degradation products, or residual solvents in a drug product because their presence may affect safety, efficacy, and stability and can lead to adverse effects in patients.
In manufacturing plants, flue gas analysis is used for industrial efficiency and emission control. This type of gas analysis is a facile and cost-effective method for detecting the concentration of gases ejected from flues and regulating the burner on a boiler for optimal performance.
Gas analysis has substantial implications for mining operations. This analytical technique is used to monitor and analyze the concentration of gases in the mine atmosphere, which is crucial for ensuring the safety of miners.
What is Chemiluminescence Gas Analysis?
Chemiluminescence is a luminescence phenomenon that produces ultraviolet, visible, or infrared radiation due to chemical reactions. It is a highly sensitive, facile, and rapid method and produces the output without background luminescence.
Gas-phase chemiluminescence plays a crucial role in detecting and quantifying the volatile and gaseous components in the environment. Harmful contaminants in various industrial processes and products, such as refinery gas streams to important ingredients in certain spices, beverages, and condiments, may contain trace amounts of nitrogen- and sulfur-containing compounds. The high sensitivity of chemiluminescence gas analysis allows facile detection of these species.
Ozone-Induced Chemiluminescence
In the gas-phase ozone-induced chemiluminescence, a photomultiplier tube is placed in front of a reaction cell of a gas analyzer, where ozone, sourced from air or oxygen, is introduced, and the facile nitrogen/sulfur chemiluminescence-based detection and separation processes are carried out in the gas phase.
Because nitrogen or sulfur analytes do not react with ozone at room temperature, an initial pyrolysis conversion step is required to convert these unreactive compounds into chemiluminescence-detectable forms, that is, their excited forms (NO2*). Here, the de-excitation of the excited forms involves the generation of a distinctive broadband near-infrared chemiluminescence at 1200 nm, which is observed in the form of interference in the spectra.
Similarly, sulfur-containing compounds react with ozone to generate excited species (such as SO2*), and their de-excitation results in the generation of an emission spectrum in the range of 280–460 nm. Thus, ozone-induced chemiluminescence aids in the selective detection of nitrogen and sulfur in the analytes.
Cataluminescence-Based Sensors and Arrays
Gas sensors are widely used as analytical instruments for environmental protection, public safety, and emission control. These sensors detect gases either by utilizing the signals obtained from gases or by utilizing the changes in sensor materials due to their interaction with gases.
Cataluminescence-based detection uses the latter detection method, where the interaction of the sensor material with gases produces chemiluminescence. Because the catalytic reaction of gases with sensor materials proceeds without changing the solid catalyst, it is considered a transduction principle in manufacturing gas sensors, attracting much attention from academic and industrial researchers.
The sensor array consists of a collection of sensors that produce a distinct response pattern, providing a fingerprint for identifying and classifying analytes. While conventional chemical sensors help detect specific analytes, cross-reactive sensor arrays analyze and classify the composition of complex mixtures, including perfumes, flavors, and drinks.
Cross-reactive sensor arrays are fabricated from nanomaterials because they can respond to a class of volatile compounds, but the chemiluminescence intensities vary for a given analyte on different nanomaterials. Cataluminescence-based sensor arrays are known for their robustness, long lifetimes, and fast responses.
Recent Studies
An article published in Marine Pollution Bulletin reported the use of gas chromatography in combination with sulfur chemiluminescence detection as a means of oil fingerprinting. In this study, sulfur compounds were distributed in five different fresh and weathered crude oil samples, followed by their chemometric analysis.
The study results revealed a unique distribution of sulfur compounds in each crude oil sample, in which the heavy sulfur compounds remained unchanged after weathering. Thus, gas chromatography-sulfur chemiluminescence detection supported the oil spill identification.
Another article published in Plasma Chem Plasma Process reported on the impact of plasma-produced ozone on biogas chemiluminescence and pollutant emissions. This investigation used flame emission spectroscopy for flame chemiluminescence and was performed in a flat flame burner with a wide range of fuel–air equivalence ratios using different compositions of biogases. The study revealed that the addition of ozone to the flames of alternative fuels could lead to cleaner and more efficient combustion.
Water vapor barrier performance is crucial for the application of organic light-emitting diodes (OLEDs), liquid crystal displays (LCDs), thin-film transistors (TFTs), and other devices. In this regard, the adsorption of water molecules on these devices is detected in terms of water vapor transmission rate (WVTR).
An article published in Chemosensors reported the detection of water vapor by chemiluminescence using a reaction between bis(2,4,5-trichlorophenyl-6 -carbopentoxyphenyl)oxalate and hydrogen peroxide. Here, hydrogen peroxide was produced as a by-product of the reaction between sodium percarbonate and water molecules, as confirmed by mass spectrometry. This method serves as a promising technique to detect the faulty points of water barrier films in real-time failure analysis during flexibility tests at the production level.
Conclusion
Overall, chemiluminescence gas analysis is a robust analytical technique for modern scientific exploration and industrial applications. Their ability to detect and quantify trace gases in analytes with high specificity and sensitivity is bringing about major breakthroughs in environmental monitoring, industrial process control, and medical diagnostics.
This non-invasive and rapid chemiluminescence gas analysis uses the light emitted during chemical reactions for accurate detection of gases, enabling academic and industrial researchers to unravel the chemical composition of gas samples in diverse settings.
Further advancements in technology and the integration of newer nanomaterials into instrumentation can lead to advancements in the application of chemiluminescence gas analysis, especially in environmental monitoring.
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References and Further Reading
Zhang, L., Hu, J., Lv, Y., Hou, X. (2010). Recent progress in chemiluminescence for gas analysis. Applied Spectroscopy Reviews, 45(6), 474-489. https://doi.org/10.1080/05704928.2010.503527
Prasantongkolmol, T., Thongkorn, H., Sunipasa, A., Do, H. A., Saeung, C., Jongpatiwut, S. (2023). Analysis of sulfur compounds for crude oil fingerprinting using gas chromatography with sulfur chemiluminescence detector. Marine Pollution Bulletin, 186, 114344. https://doi.org/10.1016/j.marpolbul.2022.114344
Paulauskas, R., Bykov, E., Zakarauskas, K., Striūgas, N., & Skvorčinskienė, R. (2023). Effects of Plasma-Produced Ozone on Flame Chemiluminescence and Pollutant Emissions of Biogas with Different CO2 Content. Plasma Chemistry and Plasma Processing, 43(4), 831-847. https://doi.org/10.1007/s11090-023-10338-7
Shimada, T., Nishimoto, H., Hayakawa, H., Ichikawa, H., Nakacho, Y. (2023). Detection of Water Vapor by Chemiluminescence. Chemosensors, 11(5), 284. https://doi.org/10.3390/chemosensors11050284
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