title: Fluorescent ion-selective optode membranes incorporated onto a centrifugal microfluidics platform.
abstract: The development of an integrated analysis system for small ions based on ion-selective optodes and centrifugal microfluidics is reported. The performance of this system was evaluated through five-point calibration plots for two types of optode membranes, one being cation-selective and the other anion-selective, which were incorporated into a microfluidics platform on which fluid motion is induced via angular rotation. Additionally, the application of the microfluidic platform to ion analysis is studied via a two-point calibration protocol used to quantify an unknown sample. Calibrant solutions are delivered from reservoirs fabricated onto the platform to a measuring area that contains the optode membrane, with a change in membrane fluorescence being monitored. This work demonstrates the first instance of a microfluidic-based analysis system with detection based on ion-selective optode membranes monitored with fluorescence transduction. Furthermore, in addition to employing a standard excitation source where a fiber-optic probe is coupled to a tungsten-halogen lamp, laser diodes such as those employed in portable CD/DVD players were studied as excitation sources to enhance the observed fluorescence signals.
authors.affiliation: Department of Chemistry, University of Kentucky, Lexington 40506-0055, USA.
authors.forename: Ibrahim H A
authors.initials: IH
authors.lastname: Badr
authors.forename: R Daniel
authors.initials: RD
authors.lastname: Johnson
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Madou
authors.forename: Leonidas G
authors.initials: LG
authors.lastname: Bachas