Abstract: Adopting and improving the pretxeatment of determination of fluorine in foods with diffusion-spectrophotometery in the national standard,the method for determination was replaced by ion chromatography,so a new method for determinating the fluorine in fish by diffusion-ion chromatography was developed.The pH value of the solution was reduced by a home-made electrochemical neutralizer.The solution was then fit to be determinated by ion chromatography.There is linear correlationship between the mass concentration(mg/L)and peak height(nS)of the fluorine,with the coefficient of 0.9980.The detection range is 0.04～5.00 mg/L.The average recoveries of two spiked samples with 1.00,2.00 mg/L are 94.00%,98.00% respectively,and the within-day and between-day precisions are 3.93%,2.78% respectively.Limit of detection and limit of quantification are 1.58,5.25μg/L,respectively.This method would be expected to be used for the determination of micro fluorine in other biological samples.

Key words: ion chromatography, fluorine, diffusion, electrochemical neutralizer, fish