novel membranes comprising various polymers containing heterocyclic nitrogen groups are described . these membranes are usefully employed in electrochemical sensors , such as amperometric biosensors . more particularly , these membranes effectively regulate a flux of analyte to a measurement electrode in an electrochemical sensor , thereby improving the functioning of the electrochemical sensor over a significant range of analyte concentrations . electrochemical sensors equipped with such membranes are also described .