Mikrochim. Acta 107, 65-72 (1992) Mikrochimica Acta 9 by Springer-Verlag 1992 Printed in Austria 2,6-Bis[(o-hydroxy) phenyliminomethyl]- 1-hydroxybenzene as a Reagent for the Selective Spectrofluorimetric Determination of Aluminium Fermin Capitfin, Ramiro Avidad, Alberto Naval6n, and Luis F. Capit/m-Vallvey* Department of Analytical Chemistry, University of Granada, E-18071 Granada, Spain Abstract. A spectrofluorimetric method for the determination of aluminium at ng/ml level has been developed. The method is based on the formation of a fluorescent 1 : 1 complex between AI(III) and 2,6-bis [(o-hydroxy)phenylimino- methyl]-l-hydroxybenzene at an apparent pH of 5.0 in an aqueous-ethanol medium (70% v/v ethanol). The influence of reaction variables is discussed. The range of concentration of the method is 1.0-10.0 ng/ml aluminium, the relative standard deviation 1.5% and the limit of detection 0.1 ng/ml. The advantages of the proposed method include high sensitivity and selectivity. The method has been applied to the determination of Muminium in natural waters. Key words: spectrofluorimetry, aluminium determination, natural waters, 2,6- bis[(o-hydroxy) phenyliminomethyl]-l-hydroxybenzene. Assays for aluminium in body fluids and water have taken on considerable impor- tance over the past few years, ever since the metal was first suspected of being involved in cases of encephalopathy in patients with renal insufficiency treated by dialysis [1-3]. Aluminium toxicity is also associated with osteomalacy and osteodistrophy [4, 5], anaemia [6, 7], gastrointestinal symptoms [8] and possible cardio toxicity [9] features. The determination of aluminium in waters is desirable, as the most important source of this element in patients with renal failure is the water used for dilution of dialysis solutions [10, 11]. Commercial aluminium salts are used as flocculants in water-treatment plants; aluminium sulphate, chloride and chlorosulphate are the most commonly employed. This implies that flocculation with commercial aluminium salts increases the alu- minium content in tap water. Aromatic Schiff's bases of salicylidene-o-aminophenol (I) type have been exten- sively proposed for the spectrofluorimetric determination of metals, through forma- * To whom correspondence should be addressed