Publication Details

Category Text Publication
Reference Category Journals
DOI 10.3390/s16111930
Title (Primary) Approach for self-calibrating CO2 measurements with linear membrane-based gas sensors
Author Lazik, D.; Sood, P.
Source Titel Sensors
Year 2016
Department BOPHY
Volume 16
Issue 11
Page From art. 1930
Language englisch
Keywords gas sensors; membrane; internal standard; monitoring; greenhouse gases; CO2
UFZ wide themes RU1
Abstract Linear membrane-based gas sensors that can be advantageously applied for the measurement of a single gas component in large heterogeneous systems, e.g., for representative determination of CO2 in the subsurface, can be designed depending on the properties of the observation object. A resulting disadvantage is that the permeation-based sensor response depends on operating conditions, the individual site-adapted sensor geometry, the membrane material, and the target gas component. Therefore, calibration is needed, especially of the slope, which could change over several orders of magnitude. A calibration-free approach based on an internal gas standard is developed to overcome the multi-criterial slope dependency. This results in a normalization of sensor response and enables the sensor to assess the significance of measurement. The approach was proofed on the example of CO2 analysis in dry air with tubular PDMS membranes for various CO2 concentrations of an internal standard. Negligible temperature dependency was found within an 18 K range. The transformation behavior of the measurement signal and the influence of concentration variations of the internal standard on the measurement signal were shown. Offsets that were adjusted based on the stated theory for the given measurement conditions and material data from the literature were in agreement with the experimentally determined offsets. A measurement comparison with an NDIR reference sensor shows an unexpectedly low bias (<1%) of the non-calibrated sensor response, and comparable statistical uncertainty.
Persistent UFZ Identifier
Lazik, D., Sood, P. (2016):
Approach for self-calibrating CO2 measurements with linear membrane-based gas sensors
Sensors 16 (11), art. 1930 10.3390/s16111930