棉仁植酸含量的离子色谱测定方法研究

Determination of Phytic Acid in Cottonseed Kernels by Ion Chromatography

为准确测定棉仁植酸含量,本研究从提取工艺、色谱条件改进等方面入手,优化建立了棉仁植酸含量的快速提取及离子色谱测定方法：棉仁粉样品烘干后用乙醚脱脂,以10 m L 0.66 mol·L-1的HCl提取,沸水浴1 h,4℃震荡12 h,离心分离,取上清液稀释并纯化后上样分析;采用DIONEX ICS-2000离子色谱仪、AG11-HC Guard（4 mm×50 mm）保护柱和AG11-HC Analytical（4 mm×250 mm）分离柱,在30.0 mmol·L-1的KOH为淋洗液,流动相流速为1.0 m L·min-1,采样时间为25 min,抑制电流为75 m A,柱温30℃,进样量20μL的条件下进行检测。结果表明,棉仁植酸的回归曲线R2为0.999,在检测浓度内线性关系良好;各项指标相对标准偏差均在5%以内,平均回收率为98.64%~102.31%,检出限（样品中检出待测物的最小浓度）为0.059μg·m L-1,定量限（样品中待测物能被定量测定的最低量）为0.196μg·m L-1。

Cottonseed meal is an important plant protein resource of feed industry and breeding industry, although it contains many antinutritional factors. Phytic acid, as one of the mainly antinutritional factor, cannot be digested easily by monogastric animals, such as fowls and pigs, consequently results in the decreased bio-availability of material elements and leads to the environment pollution by the phytate in excreta. Thus far, study of breeding cottons containing low phytic acid gradually becomes the hotspot, and the method of fully extracting phytic acid from cotton seeds and precise measurement is becoming more and more important and necessary. A new method for the rapid extraction and determination of phytic acid in cottonseed kernels by ion chromatography was developed in this study. After the diethyl ether treatment of dry cottonseed kernel powder, the samples were suspended in 10 ml 0.66 mol·L-1HCl and boiled for 1 hour. Then the samples were shaken at 4 ℃ for 12 hours and centrifuged. The supernatant was diluted and purified for loading. To analyze the sample, DIONEX ICS-2000 ion chromatography,AG11-HC Guard（4 mm×50 mm） protection column and AG11-HC Guard（4 mm×250 mm） separation column were used in controlled conditions（washing buffer： 30.0 mmol·L-1KOH; ream speed： 1.0 m L·min-1; collecting time： 25 min; 75 m A current; temperature： 30 ℃; loading amount： 20 μL）. The results showed that R2 of linear regression is 0.999, which means the regression relation is great. In addition, the standard deviations of all the indexes are within 5% and the average recovery rate is98.64%-102.31%. The detection limit, showing the minimum detectable concentration of analyte in the sample, is 0.059 μg·m L-1, and the quantitation limit, showing the minimum amount of analyte in a sample can be quantitatively determined, is 0.196μg·m L-1. This method is easy and accurate with great reproducibility, showing a strong application value.