Fluorous nano oil droplet-loaded colorimetric paper-based analytical device for selective enrichment and detection of perfluorooctanesulfonate.

A fluorous nano oil droplet-loaded paper-based analytical device (PAD) was fabricated for simultaneous selective enrichment and colorimetric detection of perfluorooctanesulfonate (PFOS-) during sample flow-through. Increasing sample volume yielded up to 18-fold PFOS- enrichment and enhanced detection sensitivity, whereas interfering anions without fluoroalkyl chains showed no enrichment, demonstrating selective enrichment based on fluorous interactions.