High sensitive flow injection analysis for fluoride by using alfusone solution containing fluoride

Original Paper

Abstract

Many spectrophotometric methods by FIA have been reported in the literature, which are based on the reaction of fluoride with lanthanum alizarin. In those methods, acetone was added to the reagent solution to enhance sensitivity. But, it is preferable to avoid the addition of acetone in the system with a peristaltic pump. In this study, the chemical factors and FIA variables influencing color development were examined using an alfusone reagent solution without acetone and a compact manifold, which consists of an all-in-one peristaltic pump, injector, thermostat and photometric detector. The absorbance was measured at 620 nm. The constant and maximum absorbance was obtained at a flow rate of 0.51 mL/min and a reaction temperature of 60°C, when alfusone solution (6 g/L) containing fluoride (0.6 mg/L) was used as the reagent solution. Under optimum conditions, with 400μL sample injection the calibration graph was linear from 0.008 to 0.8 mg/L of fluoride. The relative standard deviation was ca.4 % ( ｎ = 5) at the 0.008 mg/L level.