A new fluorescent reagent, SPAEC, was synthesized. The acidic dissociation constants were estimated by the isobestic point method, pK1 = 3.42, pK2 = 5.46, pK3 = 7.99. SPAEC forms color and/or fluorescent chelates with Al3+, Ga3+, In3+, Sc3+, Fe3+, Cu2+, Zr4+, Hf4+, and some of rare earth ions. The optimal conditions for fluorescent chelating formation between SPAEC and Ga3+ or Al3+ ion were established. At pH 3.8 to 5.4, with lex and lem at 515 and 585 nm, resp., quantum yield was 0.046 for Ga3+. For Al3+, at pH 4.0 to 5.5 and the lex and lem at 535(or 520) and 575 nm, resp., quantum yield was 0.104. The SPAEC chelates were 1:1 type for both Ga3+ and Al3+. The proposed method can be used for determination of 15-150 ppb Ga and 1.5-30 ppb Al in alloy and semiconductor samples with satisfactory results. Finally, a method for simultaneous determination of Ala nd Ga using SPAEC was developed by Kalman filter-fluorometry. This method improves the selectivity of a highly sensitive fluorometric method.

Key words: FLUORIMETRIC ANALYSIS, PHENOL P, SULFO GROUP, ALUMINIUM, ANALYTICAL CHEMISTRY, ANALYTICAL CHARACTERISTICS, AZO COMPOUNDS, GALLIUM, FLUORESCENT REAGENT, ETHYLAMINO GROUP