Highly Sensitive Paper-based Analytical Devices with the Introduction of a Large-Volume Sample via Continuous Flow.

The implementation of continuous flow in paper-based analytical devices (PADs) was challenging because of the large-volume introduction that was created; but this allowed for the development of novel types of PADs for preconcentration, separation, and sensitive detection. In this study, pump-free continuous flow was applied to a distance-based PAD for the determination of iron ions. Continuous flow enabled the introduction of a volume that exceeded what was necessary to fill the hydrophilic channel of a PAD.