title: Site-selective nitrogen isotopic ratio measurement of nitrous oxide using a TE-cooled CW-RT-QCL based spectrometer.
abstract: The feasibility of laser spectroscopic isotopic composition measurements of atmospheric N2O was demonstrated, although making them useful will require further improvements. The system relies on a thermoelectrically (TE) cooled continuous-wave (CW) room temperature (RT) quantum cascade laser source emitting wavelength of around 4.6μm, where strong fundamental absorption bands occur for the considered specie and its isotopomers. The analysis technique is based on wavelength modulation spectroscopy with second-harmonic detection and the combination of long-path absorption cell. Primary laboratory tests have been performed to estimate the achievable detection limits and the signal reproducibility levels in view of possible measurements of (15)N/(14)N and (18)O/(16)O isotope ratios. The experiment results showed that the site-selective (15)N/(14)N ratio can be measured with a precision of 3‰ with 90s averaging time using natural-abundance N2O sample of 12.7ppm.
authors: Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education, Anhui University, Hefei, China. Electronic address: jingsong_li@ahu.edu.cn.
authors: Jingsong
authors: J
authors: Li
authors: School of Science, Tianjin University of Technology and Education, Tianjin, China.
authors: Lizhu
authors: L
authors: Zhang
authors: Key Laboratory of Opto-Electronic Information Acquisition and Manipulation of Ministry of Education, Anhui University, Hefei, China.
authors: Benli
authors: B
authors: Yu
mesh_terms: D004784:Environmental Monitoring / Q000295:instrumentation; D004867:Equipment Design; D007834:Lasers; D009587:Nitrogen Isotopes / Q000032:analysis; D009609:Nitrous Oxide / Q000032:analysis*; D015203:Reproducibility of Results; D013057:Spectrum Analysis / Q000295:instrumentation*; D013696:Temperature
chemical_list: D009587:Nitrogen Isotopes; D009609:Nitrous Oxide
keywords: Isotope analysis; Laser spectroscopy; Nitrous oxide; QCL spectrometer