title: Microfluidic ion-sensing devices.
abstract: Quantitative determinations of ions in a variety of media have been performed traditionally via one of three approaches: optical instrumental methods (e.g., atomic absorption, and inductively-coupled plasma-optical emission or mass spectrometry), "wet" methods, or ion-selective sensors. Each of the approaches, though, possesses limitations including: power/reagent consumption and lack of portability for instrumental techniques; laborious sample-treatment steps for wet methods; and lack of selectivity and sensitivity with sensors when employed with complex samples. Microfluidic device have emerged as a solution to some of these challenges associated with ion analysis. Such systems can integrate multiple sample handling, calibration, and detection steps ("lab-on-a-chip" concept) into a footprint amenable to portability, while requiring small amounts of sample and power. Furthermore, devices can be constructed for multi-analyte detection, either through multiple parallel fluidic architectures or by using arrays of detection elements. This paper reviews recent progress in the development of total-analysis systems for ionic species. Fabrication techniques and various fluid-handling operations are discussed briefly, followed by a number of more mature strategies for microfluidic ion analysis. A variety of approaches expected to comprise the next generation of devices are also presented.
authors: Department of Chemistry, Murray State University, Murray, KY 42071-3346, USA. daniel.johnson@murraystate.edu
authors: R Daniel
authors: RD
authors: Johnson
authors: Vasilis G
authors: VG
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authors: Sylvia
authors: S
authors: Daunert
authors: Leonidas G
authors: LG
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