Optical fiber chemical sensing of anionic surfactants using a microfluidic polymer chip with embedded ion-selective fluorescence optode.

This study introduces a novel microfluidic polymer chip system that employs an embedded anionic surfactant (AS) ion-selective fluorescence optode (AS fluorescence optode) as a detector for measuring AS. The AS fluorescent optode comprises a lactone form of rhodamine B (L-RB) embedded in 2-nitrophenyl octyl ether plasticized poly (vinyl chloride) membrane. The AS fluorescence optode demonstrated a linear correlation between fluorescence intensity peak heights and AS concentrations within the range of less than 20 µM under optimal flow conditions. The limit of detection for AS was approximately 0.06 µM. The microfluidic system was utilized to measure AS levels in environmental samples, such as river water and tap water.