Solid Phase Extraction Using Polymer-Based C18 Cartridge Modified with 5-(2‘-Methyl-4‘-Hydroxyphenylazo)-6-Hydroxypyrimidine-2,4-Dione for Spectrophotometric Determination of Indium(III) in Water and Real Samples

Abstract

A novel highly selective, sensitive, and rapid procedure to determine nano-gram amount of In(III) depended on the speed reaction of In(III) with 5-(2‘-methyl-4‘-hydroxyphenylazo)-6-hydroxypyrimidine-2,4-dione (MHH-PD) and the colored complex extracted using solid phase extraction (SPE) have been developed. The interaction of MHHPD with In(III) to form a molar ratio 3: 1 [MHHPD to In(III)] violet complex is investigated in the presence of 3.0 M of nitric acid solution and Triton X-100 medium. The formed complex was enriched by SPE using a polymer-based C18 cartridge. In the reverse direction, the retained complex is eluted from the cartridge at a flow rate of 5.0 mL min^–1 with 0.5 mL of acetonitrile. The enrichment factor of 200 was achieved. The molar absorptivity of the formed complex is 8.81 x ?10⁸ L mol^–1 cm^–1 at 622 nm. Beer’s law is obeyed in the range of 2.5-95 ng mL^–1, whereas the optimum concentration ranges obtained from Ringbom plot was 5.0-90 ng mL^–1. The relative standard deviation (RSD) for ten replicates sample of 60 ng mL^–1 level is 1.15 %. The detection and quantification limits, are 0.75 and 2.47 ng mL^–1. The proposed procedure was successfully applied to determine In(III) in sea, river, tap and waste waters, soil and sediment samples with good results comparing to the GFAAS method.

Key words:

• Solid phase extraction
• indium determination
• pyrimidine azo dyes
• spectrophotometry
• water and environmental analysis