测定食品的氟有扩散—氟试剂比色法、灰化蒸馏—氟试剂比色法、氟离子选择电极法[1]等方法,但这些方法操作很繁琐,其中氟离子选择电极法还需要大量的总离子强度缓冲液。笔者改用高氯酸浸提水果样品后,不需要加离子强度缓冲液,可直接用氟电极测定氟浓度,方法简单、方便。1原理溶液中的氟在pH等于1的情况下主要以HF络合状态存在,大约仅有1%的氟处于游离状态。由于氟电极的检出下限为10-6～10-7mol/L,所以仍能检出很少量的氟。当电极插入被测液和加标后的被测液时 Determination of food fluorine diffusion - fluorine reagent colorimetric, ashing distillation - fluorine reagent colorimetry, fluoride ion selective electrode method [1] and other methods, but these methods are cumbersome to operate, including fluoride ion selective electrode method also requires a large amount Total ionic strength buffer. The author switched to perchloric acid extraction of fruit samples, do not need to add ionic strength buffer, fluorine electrode can be directly measured fluorine concentration, the method is simple and convenient. 1 Principle The fluorine in the solution is mainly in the form of HF complex at pH 1 and only about 1% of the fluorine is in the free state. Since the detection limit of the fluorine electrode is 10-6 ~ 10-7mol / L, a small amount of fluorine can still be detected. When the electrode is inserted into the test fluid and the spiked test fluid