Quantum Cascade Laser Infrared Spectroscopy for Online Monitoring of Hydroxylamine Nitrate

Abstract

We describe a new approach for high sensitivity and real-time online measurements to monitor the kinetics in the processing of nuclear materials and other chemical reactions. Mid infrared (Mid-IR) quantum cascade laser (QCL) high-resolution spectroscopy was used for rapid and continuous sampling of nitrates in aqueous and organic reactive systems, using pattern recognition analysis and high sensitivity to detect and identify chemical species. In this standoff or off-set method, the collection of a sample for analysis is not required. To perform the analysis, a flow cell was used for in situ sampling of a liquid slipstream. A prototype was designed based on attenuated total reflection (ATR) coupled with the QCL beam to detect and identify chemical changes and be deployed in hostile environments, either radiological or chemical. The limit of detection (LOD) and the limit of quantification (LOQ) at 3σ for hydroxylamine nitrate ranged from 0.3 to 3 and from 3.5 to 10 g·L−1, respectively, for the nitrate system at three peaks with wavelengths between 3.8 and 9.8 μm.

Recent Advances in Nanomaterial-Based Human Breath Analytical Technology for Clinical Diagnosis and the Way Forward

“…93 For instance, quantum cascade laser spectroscopy was reported to be more advantageous than Fourier-transform infrared spectroscopy in terms of portability and spectral resolution. 96 Laser spectroscopic analysis of target species in breath samples is usually achieved by using highly specific laser fingerprint wavelengths. The concentration of specific target species in the gas cell can then be calculated from the laser beam absorbance (Beer-Lamberts law).…”

Design of Experiments, Chemometrics, and Raman Spectroscopy for the Quantification of Hydroxylammonium, Nitrate, and Nitric Acid

“… 11 , 12 Real-time monitoring using quantum cascade laser infrared analysis has been considered. 13 , 14 Raman spectroscopy, a technique that could provide better detection limits and several operational benefits for practical glove box and hot cell applications (e.g., fiber launched), has not been considered. 3 …”

“…11,12 Real-time monitoring using quantum cascade laser infrared analysis has been considered. 13,14 Raman spectroscopy, a technique that could provide better detection limits and several operational benefits for practical glove box and hot cell applications (e.g., fiber launched), has not been considered. 3 Quantitative Raman analysis is primarily based on the proportional relationship between the intensity of Raman scattered light and analyte concentration.…”

Measuring Hydroxylammonium, Nitrate, and Nitrite Concentration with Raman Spectroscopy for ²³⁸Pu Supply Program

“…Achieving real-time analysis with optical spectroscopy in a hot cell environment is challenging. 7 Online spectroscopic methods can be verified by robust chemical analyses with low detection limits applied in adjacent glove boxes and radiochemical hot cells.…”