论文部分内容阅读
粮食样品中含氟量低微,欲准确测定难度较大。最早的蒸馏-比色法,操作复杂费时,易引起污染;酸浸-电极法虽简便快速,但不适于低含量且结构紧密的粮食样品的测定。1981年Robert等人提出了扩散电极法,实验中,我们发现该方法有如下问题。1.实验中测定值一般在标准曲线的非线性部分,偏离能斯特响应,2.Robert等人的实验所用扩散时间较长,给大批样品测定带来不便。针对这些问题我们采用了Jo-seph提出的空白校正法,使标准曲线低含量弯曲部分直线化,并加大了酸的浓度,提高了扩散温度,减小了样品粒度,使扩散时间由16小时缩短到10小时,此方法可用于含氟量≥0.2ppm作物样品中氟的测定。相对标准偏差为4.9％,回收率为90—116％。
Fluorine content in food samples is low, to accurately determine the more difficult. The earliest distillation - colorimetric method, complex and time-consuming operation, easy to cause pollution; acid leaching - although the electrode method is simple and fast, but not suitable for low content and tight structure of the food sample determination. In 1981, Robert et al. Proposed a diffusion electrode method. In the experiment, we found that the method has the following problems. 1. The experimental values are generally deviations from the Nernst response in the non-linear part of the standard curve. 2. The longer diffusion times used in the experiments by Robert et al. Have caused inconveniences for a large number of samples. To solve these problems, we use the blank correction method proposed by Jo-seph, which makes the curve of low content of the standard curve straight and increases the acid concentration, increases the diffusion temperature and reduces the particle size of the sample, making the diffusion time from 16 hours Shortened to 10 hours, this method can be used for fluorine content ≥ 0.2ppm Determination of fluoride in crop samples. The relative standard deviation was 4.9% and the recovery was 90-116%.