A paper-based microfluidic analytical device combined with home-made SPE column for the colorimetric determination of copper(II) ion.

Monitoring of copper(II) ion is critical for water safety. Herein, a solid phase extraction (SPE) column filled with home-made sulfonated PS-DVB microspheres was adopted to eliminate interference from other co-existing ions. Meanwhile, 1-(2-pyridylazo)-2-naphthol (PAN) as colorimetric reactant was dispersed in polyvinyl butyral (PVB) and immobilized on the filter paper. The as-fabricated paper-based microfluidic analytical device (μPAD) combined with home-made SPE column was utilized for the selective and quantitative determination of copper(II) ion. The selectivity and sensitivity for copper(II) ion were significantly enhanced by SPE-combined μPAD. The sensor has a noticeable color change in the presence of copper(II) ion. The limit of detection was as low as 0.340 μM, which is much less than the drinking water guidelines in many countries and organizations. This technology is convenient and does not need any expensive instrumentation and professional skills. It is easily used to achieve rapid and on-site assessment of copper(II) ion in real-world situations.