Establishment and application of solvent extraction coupled with ftir spectroscopy method for trace water in oil analysis

FTIR analysis of moisture in edible oils coupled with solvent extraction has been examined in the paper. The results suggested that acetonitrile was the optimal extraction solvent. On condition being less than 300 μg/g, initial moisture in acetonitrile had no significant effect on extraction capability. The acetonitrile to edible oil ratio of 1.5~2:1 was fit. When based on gap-segment 2nd derivative processed spectra, quantitative analysis could be more accuracy than that being based on differential spectra. It had a higher sensitivity in the 1640 cm-1as opposed to 3630 cm-1and 3541 cm-1. On optimal conditions, the SD of calibration curve could be 3.3 μg/g. For all the tested samples, FTIR results could well match those determined by Karl Fisher method, and showed fine accuracy and precision (with a SD of 30 and relative standard deviation of 3%). It was proved that the analysis of moisture in edible oil by FTIR combined with solvent extraction was feasible. © 2015, Editorial Department, Chinese Cereals and Oils Association. All right reserved.