Potassium selective quartz crystal microbalance chemical sensors using functionalized copolymer coatings

Quartz crystal microbalance sensors that specifically detect K+ ions have been developed using copolymers based on poly(acrylic acid) and functionalised with crown ethers to provide selectivity. The coatings selectively absorb K+ over other Group I ions such as Li+ and Na+. Sensors have been used in both batch and flow modes with detection limits in the region of 0.1-0.2 ppm for K-(aq)(+) with a linear range extending to over 1000ppm. The sensors perform at least as well as other recently developed methodologies although further optimisation should significantly improve this performance. (c) 2005 Elsevier B.V. All rights reserved.