Performance Evaluation of a Portable Infrared Gas Analyser Based on Fourier Infrared Spectral Analysis Technique

The performance of a portable infrared gas analyzer based on Fourier transform infrared spectroscopy (FTIR) technology was evaluated for environmental monitoring and gas emission detection. The instrument comprises a solid-state laser, SiC infrared light source, Michelson interferometer, and software system incorporating instrument management, measurement management, and data management modules, providing technical support for high-precision measurements. Performance verification was conducted through traceability calibration and testing with various concentration gases including C₃H₈, CO₂, NO, and NO₂. Experimental tests spanned gas concentrations from 20 μmol/mol down to 1 μmol/mol, showing close agreement between measured values and setpoints with minor indication errors: C₃H₈ (−0.24 to 0.02) μmol/mol, CO₂ (−0.64 to 0.12 )μmol/mol, NO (0.075 to 0.12 )μmol/mol, and NO₂ (0.08 to 0.15) μmol/mol. Repeatability tests demonstrated a standard deviation of 0.04 μmol/mol for CO over 10 measurements. Uncertainty analysis revealed relative expanded uncertainties of 1.43% (k=2) for C₃H₈, 1.45% (k=2) for CO₂, 1.53% (k=2) for NO, and 1.43% (k=2) for NO₂. These results confirm the instrument's high accuracy, excellent linear response, and measurement reliability for environmental monitoring and emission detection applications. While preliminary validation demonstrates application potential, limitations include incomplete testing of all gas components and absence of long-term stability evaluation. Future research should expand test scope and conduct extended operational assessments.