ANOVA AND FACTOR-ANALYSIS APPLIED TO TIME-DOMAIN NMR SIGNALS

Time domain (or low resolution pulse) NMR can generate a range of rela xation curves (CPMG, ER, PS, HSE, FID, etc.) which may vary depending on the characteristic of the product being controlled-water content, h ydration state, solid fat content, iodine number or even authenticity of origin, Very often, the NMR signal is decomposed into a sum of expo nential relaxation curves and the calculated NMR parameters (e.g. R-1, R-2, M-0) are correlated with the property under study. Chemometric t echniques, such as analysis of variance (ANOVA) and factor analysis, w ere shown to be effective means of determining whether a given set of NMR signals contains any interesting information before proceeding to use fastidious and often uncertain signal decomposition procedures. Th ese techniques were applied to NMR signals acquired for spreads and ge latines with different compositions, to mixtures of a cation (Cu2+) an d a ligand (tetraphenylporphin) and to glycine solutions at different pH values. (C) 1997 John Wiley & Sons, Ltd.