加标浓度直读法快速测定大蒜中微量氟的研究

目的]建立一种快速测定食品中微量氟的新方法。方法]用超声波浸提法提取大蒜中的氟离子，利用离子选择性电极在加入标准溶液后直接读取样品液的氟浓度。结果]大蒜的水分含量平均值为77．730％，其RSD为2．1％。各因素对样品液氟含量的影响依次为：超声温度〉料液比〉超声时间，大蒜氟离子的最佳提取工艺：料液比为0．5：25．0，在25℃下超声提取3min。氟电极的斜率转换系数为97．9％。试验测得样品液氟含量的平均值为29．076μg／g，其RSD为2．6％。在测定样品液氟含量条件下，10．00μmol／L氟标准液氟含量的平均测定值为9．875μmol／L，相对误差为-1．25％。结论]利用离子选择性电极，结合加标浓度直读法与超声波浸提技术快速测定大蒜中微量氟的方法简便、直观，适用于现场快速测定。

Research on the Rapid Determination of Micro-fluorine in Garlic by the Method of Direct-reading Concentration after Standard Addition

Objective] The aim was to set up a new method for determining the micro-fluorine in food rapidly.Method] The fluorine ions were extracted from garlic by ultrasonic extraction,by using ion selective electrode,the fluorine concn.of sample solutions were read directly after adding standard solution.Result] The average value of water content in garlic was 77.730% and its RSD was 2.1%.The influences of various factors on the fluorine contents in sample solutions were as follows:ultrasonic temperature > ratio ...