| Abstract: | A potentiometric, enantioselective membrane electrode based on graphite paste (graphite powder and paraffin oil) has been constructed. The graphite paste is impregnated with a 10−3 mol/L 2‐hydroxy‐3‐trimethylammoniopropyl‐β‐cyclodextrin (as chloride salt) solution. The potentiometric, enantioselective membrane electrode can be used reliably for enantiopurity tests of S‐perindopril using a chronopotentiometric (zero current) technique, in the 10−5–10−2 mol/L concentration range (detection limit 5 × 10−6 mol/L), with an average recovery of 99.58% (RSD = 0.33%). The enantioselectivity was determined over R‐perindopril and d ‐proline. The response characteristics of the enantioselective, potentiometric membrane electrode were also determined for R‐perindopril. It was shown that l ‐proline is the main interfering compound. The surface of the electrode can be regenerated simply by polishing, obtaining a fresh surface ready to be used in a new assay. Chirality 11:631–634, 1999. © 1999 Wiley‐Liss, Inc. |
