A NEW CONSTRUCTION FOR POTENTIOMETRIC, ENANTIOSELECTIVE MEMBRANE ELECTRODES, AND USE FOR L-PROLINE ASSAY

A novel potentiometric, enantioselective membrane electrode based on g raphite paste (graphite powder and paraffin oil) has been constructed. The graphite paste is impregnated with hydroxy-3-trimethylammonioprop yl-beta-cyclodextrin (as chloride salt) solution, 10(-3) mol/L. The po tentiometric, enantioselective membrane electrode can be used reliably for L- proline assay with the chronopotentiometry (zero current) tech nique, in the 5.0 x 10(-5) - 1.5 x 10(-1) mol/L concentration range (d etection limit 1.0 x 10(-5) mol/L), with an average recovery of 99.90% (RSD = 0.12%). The response characteristics of the enantioselective. potentiometric membrane electrode were also determined for D-proline. The surface of the electrode can be regenerated by simple polishing ob taining a fresh surface ready to be used in a new assay.