A μPAD for simultaneous monitoring of Cu2+, Fe2+ and free chlorine in drinking water.

• A μPAD with two layers was developed to monitor Cu2+, Fe2+ and free chlorine simultaneously. • The detection limits of μPAD for single analyte were less or equal to each Chinese Drinking Water Standard concentration. • The μPAD exhibited good applicability for real use in different kinds of drinking water. Cu2+, Fe2+ and free chlorine are three important analytes in drinking water. Firstly, the μPAD for single analyte was easily fabricated. Detection limits for Cu2+, Fe2+ and free chlorine were 0.1 mg L−1, 0.1 mg L−1 and 0.2 mg L−1, respectively, less or equal to each Chinese Drinking Water Standard concentration and lower than those of most commercially available testing strips. Another μPAD with two layers was then developed to monitor and report the safety level of these three analytes in drinking water simultaneously. Moreover, the μPADs for Fe2+ and free chlorine provided more distinguishable colors to users with naked eyes. The as-fabricated μPAD not only demonstrated excellent anti-interference capability, production reproducibility, but also exhibited good applicability for real use in different kinds of drinking water. [ABSTRACT FROM AUTHOR]