Comparative Evaluation of UV/Vis Spectrophotometry and Ion Chromatography for Analyzing Low-Concentration Fluorine Compounds in Flue Gas

As emission standards for fluorine compounds have become increasingly stringent in semiconductor and electronic component manufacturing facilities, and installation restrictions have been applied to facilities with large annual emissions, the importance of accurate quantification of fluorine compounds in industrial exhaust gases has increased. In particular, low concentrations of fluorine compounds in actual exhaust gases may fall below the calibration ranges specified in the standard test methods, requiring reliable quantification in these low-concentration ranges. The standard test methods of Korea specify ultraviolet-visible (UV/Vis) spectrophotometry and ion chromatography (IC) as analytical methods for fluorine compounds in exhaust gases. However, the quantification characteristics of these methods at low concentration levels that may occur in actual exhaust gases have not been sufficiently evaluated. In this study, the quantification characteristics of UV/Vis spectrophotometry and IC were compared at both the concentration ranges specified in the standard test methods and lower concentration levels. The coefficients of determination (R²) of repeated calibration curves and the agreement between nominal and calibrated concentrations were evaluated. Both methods demonstrated acceptable quantification performance within the concentration ranges specified in the standard test methods. However, at low concentration levels, UV/Vis spectrophotometry exhibited low R² values and large discrepancies between nominal and calibrated concentrations. In contrast, IC showed relatively higher reproducibility and better agreement between nominal and calibrated concentrations. These findings suggest that IC may be more suitable than UV/Vis spectrophotometry for the analysis of low-concentration fluorine compounds.