A 3D origami paper-based analytical device combined with PVC membrane for colorimetric assay of heavy metal ions: Application to determination of Cu(II) in water samples

摘要

Microfluidic paper-based analytical devices (mu PADs) as a potentially powerful analytical platform have recently gained significant attention for on-site monitoring of heavy metal ions, which are one of the most significant environmental concern because of non-degradability and high toxicity. The commonly applied mu PADs suffers from some defects, such as heterogeneous deposition of reagent, resulting in poor detection limits and low sensitivity. So, in this work, a three-dimensional origami mu PAD combined with PVC Membrane was developed, which can manage problems of movement of colored products or leaching out the dye and leading to color heterogeneity in the detection zones. Furthermore, a waste layer was added to mu PAD for loading of more amounts of the analyte, which results in improvement of detection limit. As a proof of concept, the mu PAD was used for the analysis of Cu2+ ion. For this purpose, pyrocatechol violet and chrome azurol S as colorimetric reagents were doped into PVC membrane and injected in the detection zone. The proposed mu PAD was presented good linearity in the ranges of 5.0-1400.0 and 5.0-200.0 mg L-1, and the limits of detections of 1.7 and 1.9 mg L-1 in presence of chrome azurol S and pyrocatechol violet, respectively. (C) 2020 Elsevier B.V. All rights reserved.