Gas analysis—Fourier transform infrared spectroscopy based on comparison methods

This document specifies the principles, test conditions, reagents and materials, equipment, sampling, test procedures, comparison-method value assignment, precision, detection limits, quality assurance and control, and test reporting requirements for determining gas-component contents by Fourier transform infrared spectroscopy based on comparison measurements. It applies to gases containing polar bonds, with a molar-fraction measurement range of 0.01 × 10⁻⁶ to 1 × 10⁻². Users shall provide compliant spectroscopic measurement, gas introduction and exhaust-gas treatment systems; use qualified purge gases and suitable gas reference materials or certified reference materials; ensure instruments are verified or calibrated and within their validity period; and conduct prescribed one-point, two-point or multipoint calibration, detection-limit verification and quality control, with test reports prepared.