蔬菜中氟的测定方法研究

对国家标准GB/T 5009.18-2003《食品中氟的测定》第三法—氟离子选择电极法进行了改进研究。研究了氟离子选择电极的性能检查、pH值和温度对测定结果的影响以及标准曲线的变化规律;研究了蔬菜的样品前处理方法并优化了标准曲线,提出了加大称样量和多点校正曲线的改进方法,使结果更为准确;研究了回收率、精密度和检出限,氟离子浓度在0.02 ug/mL5.0 ug/mL的浓度范围内,加标回收率的范围为70%-115%,相对标准偏差范围为0.82%-4.94%,检出限为0.2 mg/kg。该方法适合蔬菜中氟的测定,特别是氟含量较低的蔬菜中氟的测定。

Detection Assay of Fluorine Content in Vegetables

Determination of fluorine content in vegetables by GB/T 5009.18-2000 Determination of fluorine in food the third method—Fluoride ion selective electrode method was improved in this paper.Firstly,three factors,the performance examination of fluorine ion selective electrode,the influence of PH value and temperature for the determination results and the change rules of standard curve,were studied.Secondly,the sample pretreatment method was studied and the standard curve was optimized,and a more accurate method by increasing the sample weight and multipoint calibration curve was presented.Finally,recovery,precision and the detection limit were studied,and the fluorine ion concentration was in the range of 0.02 ug/mL-5.0ug/mL,the recovery of this method ranged from 70% to 115%,the relative standard deviation,from 0.82% to 4.94%,and the detection limit was 0.02 ug/kg.Therefore,this method is suitable for the determination of fluorine in vegetables,especially low fluorine content in vegetables.Compared with the national standard,the improved method in the paper is more rational and scientific,and more practical as well.