Lab-on-a-Cable for electrochemical monitoring of phenolic contaminants

The "Lab-on-a-Cable" concept, based on scaling down an electrochemical flow system to a cable platform, is described. The system integrates the analyt e collection and the sample handling, with the electrochemical detection of the reaction product in a sealed cylindrical unit, connected to a long shi elded cable. An enzymatic assay, involving collection of a phenolic substra te, its mixing with an internally delivered tyrosinase solution, and ampero metric detection of the liberated quinone product, is used for illustrating the operation of the flow probe and demonstrating its advantages over remo te phenol sensors. The internal buffer solution ensures independence of sam ple conditions such as pH, ionic strength, or natural conditions, that comm only influences the performance of remote sensors. The "built-in'" flow pul sation of the integrated micropump is exploited for a sensitive hydrodynami c-modulation voltammetric detection of hydrazine and peroxide pollutants.