Measurement of the D/H, 18O/16O, and 17O/16O Isotope Ratios in Water by Laser Absorption Spectroscopy at 2.73 μm

Sensors

Tao Wu⁴  Weidong Chen¹  Eric Fertein¹  Pascal Masselin¹  Xiaoming Gao³  Weijun Zhang³  Yingjian Wang³  Johannes Koeth²  Daniela Br࿌kner² 

[1]Laboratoire de Physicochimie de l'Atmosphère, Université du Littoral Côte d'Opale, 189A, Av. Maurice Schumann, 59140 Dunkerque, France

[2] E-Mails:

[3]Nanoplus Nanosystems and Technologies GmbH, Oberer Kirschberg 4, 97218 Gerbrunn, Germany

[4] E-Mails:

[5]Anhui Institute of Optics & Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China

[6] E-Mails:

[7]Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China

[8] E-Mails:

关键词: isotope ratios;    water;    Kalman filtering;    laser absorption spectroscopy;   

DOI  :  10.3390/s140509027

来源: mdpi

【 摘 要 】

A compact isotope ratio laser spectrometry (IRLS) instrument was developed for simultaneous measurements of the D/H, ¹⁸O/¹⁶O and ¹⁷O/¹⁶O isotope ratios in water by laser absorption spectroscopy at 2.73 μm. Special attention is paid to the spectral data processing and implementation of a Kalman adaptive filtering to improve the measurement precision. Reduction of up to 3-fold in standard deviation in isotope ratio determination was obtained by the use of a Fourier filtering to remove undulation structure from spectrum baseline. Application of Kalman filtering enables isotope ratio measurement at 1 s time intervals with a precision (<1‰) better than that obtained by conventional 30 s averaging, while maintaining a fast system response. The implementation of the filter is described in detail and its effects on the accuracy and the precision of the isotope ratio measurements are investigated.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.