Journal
OPTICS AND LASERS IN ENGINEERING
Volume 58, Issue -, Pages 48-53Publisher
ELSEVIER SCI LTD
DOI: 10.1016/j.optlaseng.2013.12.005
Keywords
Tunable diode laser absorption spectroscopy (TDLAS); Sensor; Headspace analysis; Pressure and H2O concentration
Categories
Funding
- National Natural Science Foundation of China [11104237]
- Open Research Fund of Key Laboratory of Atmospheric Composition and Optical Radiation, Chinese Academy of Sciences [2012JJ04]
- Education Committee Foundation of Jiangsu Province [11KJB140010]
Ask authors/readers for more resources
The concentration of H2O and the pressure in the headspace of vials are simultaneously measured by a tunable diode laser sensor based on absorption spectroscopy techniques. The 7168.437 cm(-1) spectral line of H2O is chosen as the sensing transition for its strong absorption strength and being reasonably far away from its neighboring molecular transitions. In order to prevent interference absorption by ambient water vapor in the room air, a difference between the measured signal and the referenced signal is used to calculate the pressure and H2O concentration in the headspace of vials, eliminating the need for inert gas purges and calibration with known gas. The validation of the sensor is conducted in a static vial, yielding an accuracy of 1.23% for pressure and 3.81% for H2O concentration. The sensitivity of the sensor is estimated to be about 2.5 Torr for pressure and 400 ppm for H2O concentration over a 3 cm absorption path length respectively. Accurate measurements for commercial freeze-dried products demonstrate the in-line applications of the sensor for the pharmaceutical industry. (C) 2014 Published by Elsevier Ltd.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available