Electrochemiluminescence integrated with paper chromatography for separation and detection of environmental hormones

Electrochemiluminescence (ECL) is a powerful technique with the advantages of high sensitivity and a wide dynamic range. However, most of previous strategies based on ECL could only detect one analyte so that it is inevitable to investigate the selectivity and influences of interferences. Herein ECL integrated with paper chromatography was showed to be a potential platform for separation and detection of two environmental hormones (bisphenol A, BPA, and dibutyl phthalate, DBP). In our approach, carbon conductive tape was attached to an ITO glass and then modified with multi-walled carbon nanotubes (MWCNTs) and CdSe quantum dot (CdSe QDs) to fabricate the working electrodes for ECL detection. The synthesis of CdSe QDs was optimized based on their photoluminescence spectra and the ECL intensities. The modified electrode was then coupled in the paper-based analytical devices consisting of the filter paper modified with chitosan. Based on their quenching effect on the ECL emission of CdSe QDs, excellent linear relationships could be obtained between decreased ECL intensities and both the concentrations of DBP and BPA. Besides, DBP and BPA could be separated based on their retention time by tilting the filter paper for 30° and then detected with ECL. This study suggested that paper-based analytical devices could be potentially applied for separation and detection of multiple targets due to their ease of fabrication and convenient operation.