Determination of boron using ion-exclusion chromatography with postcolumn derivatization method

Abstract

1-(Salicylideneamino)-8-hydroxynaphthalene-3, 6-disulfonic acid (Azomethine H) was used for the determination of boron as a reagent in a postcolumn drivatization method.Boron was separated by ion-exclusion chromatography (IEC). The eluate was subsequently mixed with Azomethine H solution to form a complex. The complex was detected at 420nm. The reaction parameters were optimized for boron as follows : reaction coil for reaction with azomethine H, 5m×0.5mm i.d. ; concentration of Azomethine H, 0.5% in 1.5mol dm^-3 CH₃COONH₄; flow rate of the reagent, 0.8 cm³min^-1; reaction temperature, 40°C. The chromatographic conditions were as follows : column, IEC column (150mm×7.8mm i.d.) packed with hydrogen form sulfonated polystyrene gel (ion exchange capacity : 3.5meq g^-1·dry) ; mobile phase, 1×10^-3mol dm^-3 sulfuric acid ;flow rate, 1.0 cm³min^-1; detection wavelength, 420nm. The detection limit (S/N=3)for boron was 7.9×10^-3mg dm^-3. The linear range was over 3 orders of magnitude, from 0.01 to 10 mg dm^-3. The relative standard deviation (RSD) was 5.5% (n=10) for 0.02 mg dm^-3boron solution. The relationship between the postcolumn-IEC method and ICP-MS showed good correlation (r²=0.921, n=50).