Calibration procedures for tunable diode laser spectrometers
Authors: Muecke Robert J., Scheumann Bodo, Slemr Franz, Werle Peter W.
Autors Affiliation: Fraunhofer Inst. fuer, Atmosphaerische Umweltforschung,, Garmisch-Partenkirchen, Germany
Abstract: The reliable operation of a TDLAS instrument for measurement of trace gas species requires a unit providing calibration gases with mixing ratios in the range of measured concentrations. It is obvious that, especially at sub-ppb-levels, calibration becomes difficult. Therefore in this paper we focus on calibration procedures for an integrated tunable diode laser spectrometer. An automated calibration system based on permeation devices with a subsequent dilution will be presented. The system meets the ISO requirements and can be used as a secondary standard for field measurements. With this instrument multi-component calibration can be performed as well as multi stage calibration. According to the ISO regulations, procedures to check the linearity and to record the calibration function for a TDL system will be described. From this calibration function the detection and determination limit can be determined by an inverse regression procedure. Some measurements will be presented and discussed under quality control and quality assurance aspects.
KeyWords: Calibration; Gases; Quality assurance; Quality control; Trace analysis, Automated calibration; Detection limit; Integrated tunable diode laser spectrometers; Mixing ratios; Multi component calibration; Secondary standards; Tunable diode lasers, SpectrometersDOI: 10000000000