Method of determining AL3+ or FE3+ cations in an aqueous medium

Solid support in the form of solid resin particles, preferably in the form of balls, useful for selective extraction of aluminum and ferric cations, comprises a crosslinked benzene polymer. The polymer (A) is present at the surface of the particles comprising a salicylic acid radical grafted on the benzene ring of the polymer through a bridging ketone. Solid support in the form of solid resin particles, preferably in the form of balls, useful for selective extraction of aluminum and ferric cations, comprises a crosslinked benzene polymer. The polymer of formula (A) is present at the surface of the particles comprising a salicylic acid radical grafted on the benzene ring of the polymer through a bridging ketone. Independent claims are included for: (1) preparation of the modified solid support comprising fixing an acetyl radical on benzene rings of the polymer by a Friedel-Crafts acylation reaction, oxidizing the acetyl radical to a carboxylic acid radical, followed by converting the acid radical into an acid chloride radical, converting the acid chloride radical into a 2-methylanisole radical by a Friedel-Crafts reaction, oxidizing the methyl group of the 2-methylanisole radical in to a carboxylic acid group and hydrolyzing the methoxy group of the 2-methylanisole radical in to a hydroxyl group; (2) a process of measuring aluminum and ferric ions in an aqueous solution using the solid support solution comprising taking a sample of the aqueous medium of known volume, adjusting the pH of the sample to a value of the pH of 2-3.5 to measure the ferric ions or a pH value of 1.6-3.5 to measure aluminum ions, percolating the sample through a column containing the solid support, eluting the column with an acid solution of pH less than 2, preferably 0.1-1, mixing the eluate with a detecting composition having a complexing agent to detect the detectable cations, which are in the form of complex, preferably by spectrophotometry or spectrofluorometry method and measuring the cations by quantifying the ionic complexes using spectrophotometry or spectrofluorometry method; and (3) an in-situ analytical device by injection in flow used for the measurement process comprising an assembly having automatically operating burettes or syringes and electrically operating valves to control the entry and flow of the samples, the complexing agents and water, a micro column containing the solid support, an assembly containing the complexing agents and water to adjust the pH of the sa