Waveband Selection with Stability for FTIR/ATR Spectroscopic Analysis of COD in Sugar Refinery Wastewater

Fourier transform infrared spectroscopy (FTIR) and attenuated total reflection (ATR) technology were successfully applied for the rapid no-reagent determination of chemical oxygen demand (COD) in sugar refinery wastewater. An appropriate waveband with stability was selected by the moving window partial least-squares (MWPLS) regression through a rigorous modeling process. The selected waveband was 3198 cm-1 to 2376 cm-1, the corresponding PLS factor was 5. The modeling effect M-SEPAve, M-RP,Ave, M-SEPStd, and M-RP,Std were 31.5 mg/L, 0.962, 3.9 mg/L, and 0.012, respectively. The validation effect V-SEP and V-RP were 31.9 mg/L and 0.965, respectively. It indicated that the method has good prediction effect and stability, and provided valuable references for designing specialized spectroscopic instruments.