ESTIMATION Of PARTICLE SIZE bY DRIFTS and FTIR-PAS

Abstract

Diffise reflectance infrared Fourier transform spectroscopy (DRIFTS) and Fourier transform infrared photoacoustic spectroscapy (FTIR-PAS) wcre used to study panicle size and distribution of sucrose powder. Partial least squares (PLS) regression was used to correlate spectral data with particle size. FTIR-PAS spectra were similar to the spectra obtained using DRIFTS when the sample is mixed with 95% potassium bromide (KBr). Both DRIFTS and FTIR-PAS methods can successfully predict the mean panicle size and concentration in binary and quaternary mixtures. R-square values for both DRIFTS and FTIR-PAS are greater than 0.9.

Rapid determination of vitamin C by NIR, MIR and FT-Raman techniques

“…Mixing a powdered sample with KBr for quantitative analysis avoids eOE ects of non-linearity and saturation in the DRIFTS spectrum. However, direct analysis of powdered samples using DRIFTS, without mixing with KBr, was successfully accomplished in conjunction with chemometrics (Reeves & Zapf 1998 ;Yang & Irudayaraj 1999). The work presented here explores DRIFTS analysis without sample preparation.…”

“…A more recent non-destructive procedure using FTIR photoacoustic (FTIR-PAS) spectroscopy was also used in vitamin C analysis. Details of FTIR-PAS for powder analysis have been published by Yang & Irudayaraj (1999).…”

Effect of concentration, particle size and the presence of protective coatings in DRIFT spectra of building materials

“…Unlike the findings for limestone, where good spectra were obtained in samples with a particle size of up to 125 mm, in granite the presence of a larger number of variables, a result of its polymineral nature (lack of mix homogeneity, different refraction index for the mineral species, different particle morphology, which in turn conditions packing, and so on), intensified the distortion induced by specular reflection [21].…”

“…Even in the most diluted series (most favourable condition for analysis because it minimizes the specular component [4,21], at particle sizes of 90 mm or over, the spectrum did not even retain its characteristic shape (B5-5).…”