Spectrophotofluorimetric Determination of Trace Amounts of Aluminium with 2,2′-Dihydroxy-3,3′-dicarboxy-1, 1′-Dinaphthylmethane (Pamoic Acid)

Abstract

Abstract Fluorescence properties of 2,2′-dihydroxy-3,3′-dicarboxy -1,1′-dinaphthylmethane (pamoic acid) and of its aluminium 1:1 complex are described. The fluorescence of the latter, as measured from a water-dioxane (3:7, v/v) solution, at pH 5.05–5.20, at room temperature, is used as a basis for a new method of aluminium determination at submicrogram level. Limit of quantification of the proposed procedure is 0.028 ng.ml−1, range of applicability goes up to 1.7 ug.ml−1, RSD is 1% at 0.47 ug.ml−1 level (concentrations, given refer to HCl solution which is measured) Tolerance ratios for several interferent metal ions are given. A comparison is made with Kirkbright's method which uses 3-hydroxy-2-naphthoic acid as complexing agent: stability with time of the readings and freedom from Fe(III) interference are the main advantages of the proposed procedure. The new method is applied to the aluminium determination in atmospheric aerosol samples.