The objective of this SBIR research is to develop a new, generic, immunoelectrochemical sensor system with capabilities for rapid, on-site, quantitative determination of biologically important molecules in fluids such as blood, plasma, serum, saliva, and urine. The principle is based on an enzyme-amplified, immunoelectrochemical, solid phase detector that can be coupled to different reporter-amplifier systems. Feasibility was demonstrated in Phase I. When complete, a user should only need to inject a sample into an analyte-specific, disposal cartridge and insert it into an analytical module. After a few minutes the measured concentration will be displayed. Phase II research will focus on optimizing the system; developing an easily-used instrument that obviates the need for pipetting; and developing and testing prototype systems able to attract Phase III support for commercialization. Specificity will be achieved through use of discriminating anti-analyte monoclonal antibodies and sensitivity through enzyme amplification and amperometric detection of generated reaction products. The developed sensor will feature low cost, electrode stability (negligible fouling),l one-step operation, and point of use calibration. If the sensor system functions as we anticipate, the capability of the sensor could be extended to the detection and quantitation of a wide variety of agents including environmental toxins, infectious agents, antibodies, drugs of abuse, diagnostic biomolecules and therapeutic drugs.