FLUOROMETRIC-DETERMINATION OF MALONATE IO N BY A FIA BASED ON THE FORMATION OF AN ALUMINUM-SCHIFF BASE COMPLEX

Salicylaldehyde reacts with a large excess of ethylenediamine to form N-salicylidene-ethylenediamine (SED). In the presence of malonate ion, SED reacted with aluminium to form a ternary fluorescent aluminium-Sc hiff base complex. The fluorescent determination of malonate ions usin g this reaction by triple-channel FIA was investigated. The fluorescen ce intensities of this complex were proportional to the concentration of malonate ions; the malonate ions in the sample solution were calcul ated based on the fluorescence peak height. The malonate ions could be selectively determined over the range 0.15 approximately 20 ppm; 40 s amples could be analyzed per hour. The proposed method was applied to determine the malonate in an alkaline solution of barbituric acid. Fur thermore, a simultaneous determination of the malonate ion and the oxa late ion was investigated by the addition of calcium chloride. Each co ncentration of malonate and oxalate ions could be calculated based on the decrease of the peak height in the presence of calcium.