The effect of HNO3, HCl and HBr on the fluorescence of the aluminium complex of l-(2-pyridylazo)-2-naphthol, and an improved fluorometric procedure for determination of aluminium

The fluorescence of the aluminium complex of 1-(2-pyridylazo)-2-naphthol (PAN) is both stabilized and enhanced by 10‚Äöv†v¿3 M HNO3 . HCl or HBr. Other acids tested have no effect. An improved flourometric procedure with a detection limit of 0,001 ppm, increased precision and reduced interferences over the existing Al‚ÄövÑvÆPAN method is described. It is satisfactory for the determination of aluminium in bronze when an ion-exchange separation is used, but is not suitable for the determination of aluminium in plants. The acidified Al‚ÄövÑvÆPAN is unsuitable for the determination of nickel(II) and fluoride by fluorescence quenching.