科研之友
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摘要
In the present study, a new flow injection (FI) methodology for determination of free fatty acid (FFA) content in corn oil samples is proposed. The proposed method is based on monitoring the absorbance changes at 580 nm, lambda (max), as a result of neutralization of FFA in oil samples by KOH in the reagent. The analyses were performed with a single-line FI manifold system created by modification of high performance liquid chromatography. The main parameters, such as sample and reagent volumes, reaction coil, reagent concentration and temperature were all optimized. With the newly developed sampling strategy, the oil sample and reagent at micro level were directly injected together without any pre-treatment. The proposed flow injection analysis method was validated statistically and it was found to be linear (between 0.09 and 1.50 FFA %), accurate (recovery 87.19-122.22 %), and precise (relative standard deviation < 1 % for both intra-day and inter-day precision). The limit of detection and limit of quantification were found to be 7.41 x 10(-3) and 2.24 x 10(-2) oleic acid %, respectively. The results were also compared with those obtained by the American Oil Chemists Society (Ca-5a-40) method using statistical t and F tests, and a significant difference was not observed between the methods at the 95 % confidence level. These results strongly suggest that this method is suitable for automated routine analysis of FFA in edible oils due to its simplicity, reliability, speed, and economy of solvents and sample.
- 出版日期2014-4
