Further development of a prototype receptor-based biosensor, or 'receptrode', utilizing the intact chemosensing structures of Callinectes sapidus is reported. Significant gains in lifetime extension of the system have been made. Also, an expansion of the list of analytes to which the receptrode responds is reported. Data are presented which indicate that the receptrode can be used to quantify some biologically important purine compounds, as well as the amino acids previously reported. The receptrode responds to stimuli concentrations over six orders of magnitude, with a high degree of specificity and a response time on the order of milliseconds. Approximately two minutes are required for the system to return to baseline, providing the limit for the analysis time. The rapid analysis time, large overall dynamic range of detection, and the high degree of specificity demonstrate the receptrode's potential as a powerful tool for chemical analysis in the future.