1. A device for detecting the presence of an analyte in a fluid having an aqueous solvent, said device comprising: a sensing capacitor including: a substrate having a first conductor and a second conductor spaced a distance from said first conductor, an electrically insulating layer covering said first and second conductors, said electrically insulating layer defining a surface, a binding agent selected from the group consisting of antigens, haptens, bioreceptors and antibodies capable of biospecifically binding with the analyte, a linking molecule adapted for and covalently bonding said binding agent to said surface and extending said binding agent a distance from said surface to minimize steric hindrance between the analyte and the surface; and, a circuit means, electrically coupled to said sensing capacitor, responsive to changes in capacitance between said first and second conductors.