溶剂萃取耦合 FTIR 技术快速分析食用油中微量水分的研究

摘要

研究应用溶剂萃取耦合傅里叶红外光谱（FTIR）技术建立快速分析食用油中微量水分的方法。数据显示乙腈是最佳萃取溶剂，其起始含水量＜300μg／g 时对乙腈的萃取能力无明显影响。乙腈／油脂比例为1.5～2∶1效果较佳，定量基于差谱的二阶导数明显优于差谱，对于萃取水分的乙腈波谱中 HOH 弯曲振动1631 cm －1最优，灵敏度高于 OH 伸缩振动3630 cm －1和3541 cm －1。对所有测试样品，FTIR 法的结果与标准卡尔费休法高度一致，并表现出优良的准确性和精确性（标准差～30，变异系数3％）。研究表明溶剂萃取耦合FTIR 快速分析食用油中微量水分切实可行。%FTIR analysis of moisture in edible oils coupled with solvent extraction has been examined in the pa-per.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 2 nd derivative processed spectra,quantitative analysis could be more accuracy than that being based on differential spectra.It had a higher sensitivity in the 1 640 cm -1 as opposed to 3 630 cm -1 and 3 541 cm -1 .On optimal conditions,the SD of calibration curve could be 3.3 μg/g.For all the test-ed 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 edi-ble oil by FTIR combined with solvent extraction was feasible.