DETERMINATION OF BORON USING ION-EXCLUSION CHROMATOGRAPHY WITH POSTCOLUMN DERIVATIZATION METHOD

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 420 nm. The reaction parameters were optimized for boron as follows: reaction coil for reaction with azomethine H, 5 m X 0.5 mm i.d.; concentration of Azomethine H, 0.5% in 1.5 mol dm-3 CH3COONH4; flow rate of the reagent, 0.8 cm3 min-1; reaction temperature, 40-degrees-C. The chromatographic conditions were as follows: column, IEC column (150 mm X 7.8 mm i.d.) packed with hydrogen form sulfonated polystyrene gel (ion exchange capacity: 3.5 meq g-1.dry); mobile phase, 1 X 10(-3) mol dm-3 sulfuric acid; flow rate, 1.0 cm3 min-1; detection wavelength, 420 nm. The detection limit (SIN=3) for boron was 7.9 X 10(-3) mg 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-3 boron solution. The relationship between the postcolumn-IEC method and ICP-MS showed good correlation (r2 = 0.921, n = 50).