Continuous-flow-injection analysis of fluoride in vegetables

The determination of fluoride is based on the alizarin fluorine blue method. After distillation at 150℃, fluoride reacts with alizarin fluorine blue/ lanthanum reagent to form a lilac - blue complex, which is measured colorimetrically when the complex absorbs at 620 nm.Determination of fluoride in Vegetables by Continuous Flow Analyzer (CFA), the linear range was 0~20 mg/L, the correlative coefficient was 0.9998, the detection limit was 0.5 mg/kg,the recovery rates were in the range 95%~102%. The method has been applied to the determination of fluoride in vegetables with satisfactory results.