Potentiometric enantioselective membrane electrode for s-enalapril assay
نویسندگان
چکیده
A novel potentiometric, enantioselective membrane electrode based on graphite paste (graphite powder and paraffin oil), impregnated with 10–3 mol/L 2-hydroxy-3-trimethylammoniopropyl-β-cyclodextrin (as chloride salt) solution, has been constructed. The potentiometric, enantioselective membrane electrode can be used for the reliable assay of S-enalapril as raw material and from its pharmaceutical formulations in the concentration range of 3.6 × 10–5 – 6.4 × 10–2 mol/L, with a detection limit of 1.0 × 10–5 mol/L and with an average recovery of 99.96% (RSD = 0.098%), using a chronopotentiometric (zero current) technique. The enantioselectivity was determined versus D-proline and it was shown that only L-proline is the main interfering compound. The surface of the electrode can be regenerated by simply polishing to obtain a fresh surface which is ready to be used in a new assay.
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