ICP-AES determination of aluminum fractions in complex environmental samples using calcon-modified anion exchange resin in SPE cartridge

A new method is presented utilizing Calcon- (1-(2-hydroxy-1-naphthylazo)-2-naphthol-4-sulphonic acid sodium salt) modified anion exchange resin in a solid-phase extraction (SPE) cartridge for the fast ICP-AES determination of aluminum (Al) fractions in complex environmental samples. It was experimentally revealed that organic monomeric Al o can be determined using the batch method, and the total monomeric Al a fraction can be detected using the column method. Inorganic monomeric Al i can be obtained easily by subtraction of Al a - Al o . There are two distinct advantages using the proposed method: (a) Good selectivity. Owing to the special functional chelating group, the Calcon-modified SPE cartridge shows good recognizing ability of Al fractions (Al a and Alo) compared with the traditionally used cation exchange resin. Total monomeric Al (Al a ) can be adsorbed on the modified resin in a wide pH range (pH 4.0-11.0) using the column procedure. Organic monomeric Al (Al o ) can be determined using the batch procedure (t 1/2 =0.7 min) since no adsorption of inorganic monomeric Al (Al i ) was found for a period up to at least 60 minutes. Thus, Al i can be obtained by subtraction of Al o - Al a . This procedure does not require adjustment of sample acidity and thus overcomes the drawbacks of other methods that change the Al species. Most matrix interferences (Fe, Mn, and organic substances) in the analysis of complex environmental samples (such as soil extracts and deep color natural waters) can be avoided with the proposed approach. (b) Simple manipulation. The modified resin is very easy to prepare by simply impregnating the solid matrix with a solution containing Calcon. The proposed method was verified by comparing the results with the classic PCV (Pyrocatechol Violet) spectrometric method. The results were found to be in good agreement. In this study, the procedure was successfully applied to the determination of three Al fractions (total monomeric Al a , inorganic monomeric Al i and organic monomeric Al o ) in complex environmental samples with a high content of organic matter.