| abstract |
Analytical sensor devices incorporating a permselective medium immobilised as a continuous liquid or gel phase barrier between sample and detector. The barrier is electrically insulating, impermeable to charged non-lipophilic species, selectively partitions lipophilic species diffusing through it, and its selectivity can be controlled or optimised by pH adjustments. The preferred barrier form has the permselective medium (e.g., a lipid or ester) immobilised by incorporation as plasticiser in a polymer (especially PVC). The preferred detector is an electrode, especially of non-potentiometric type. The sensor can be used to detect components as such or indirectly by allowing them to react to produce other materials to which the detector responds (e.g., an ionic species or an ion concentration or activity change) and is also applicable to detecting neutral or small uncharged hydrophilic species, e.g. hydrogen peroxide, especially that formed by enzyme action in the sensor or detector system. |