Abstract
The 2-aminomethylpyridine anchored silica gel (AMPSG) was successfully used as a sorbent in a simple spectrophotometric flow system for Cu2+ preconcentration in natural water samples, using sodium diethyldithiocarbamate as chromogenic agent (460 nm). The system was optimized using a full factorial design 25 to determine better analytical conditions to determine copper in the natural water samples such as those from river, tap, stream, spring, well, waste, synthetic brackish water and a water reference material (NIST-1640). The better conditions used were: 180 s loading; 30 s elution; 30 s regeneration of the column; loading flow rate 6.6 mL min−1; buffer solution for the preconcentration and regeneration of the column-acetate buffer pH 5.75; elution flow rate 1.6 mL min−1; eluent composition 0.20 mol L−1 HNO3. Under these conditions, the preconcentration factor obtained was 77, and the detection limit achieved was 3.0 ng mL−1. The recovery of spiked water samples ranged from 95.2 to 104.7%.
Acknowledgements
We are grateful to Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS), Fundação de Amparo à pesquisa do Estado de São Paulo (FAPESP), and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for financial support and fellowships.