Improvement of reproducibility for quantitative analysis of real samples by NIR FT-Raman spectroscopy using a thermal box

Near-infrared Fourier transform Raman (FT) spectroscopy is a powerful analytical method, but, quantitative analysis is often difficult owing to changes in the environmental temperature. The feasibility of using a commercial FT-Raman spectrometer (equipped with an InGaAs detector operated at room temperature) in a thermal box to obtain ±0.1 °C with minimum investment was examined for the quantitative analysis of real samples (polystyrene and cellulose). The reproducibility was improved significantly by using a thermal box and this was also demonstrated for both solid- and powder-state samples, even in the practical range of room temperature (15.0-22.0 or 22.5°C). Since the effect of both samples and laser could be ignored in this study, the thermal effect causing the decease in reproducibility was concluded to be the response of the detector.