Raman spectroscopic quantification of calcium carbonate in spiked milk powder samples

Raman spectroscopy was used to determine the limits of detection and quantification (LOD and LOQ, respectively) of calcite in spiked milk powder samples. Samples of milk powder spiked with 0.5-10% (weight by weight; w/w) calcite were prepared and analysed using FT-Raman spectroscopy. Using the spectra obtained from these samples, calibration models were prepared using peak intensities, analysis of peak intensity ratios, based on band integrals and peak heights, and multivariate analysis. Analysis methods using peak intensity, peak integral ratios and peak height ratios produced LOD values of 3.8, 3.3 and 1.4% (w/w) calcite and LOQ values of 13, 11 and 4.7% (w/w) calcite respectively. Multivariate analysis produced a LOD of 1.0% (w/w) calcite and a LOQ of 3.4% (w/w) calcite.