A NEW ALL-SOLID-STATE STREPTOMYCIN ION-SENSITIVE ELECTRODE

A new streptomycin ion-sensitive electrode of all-solid-state construction is developed. The electrode responses to both streptidine and N-methyl-Lglucosamine and shows Nernstian response down to 10-4～10^-5M streptomycin solutions over a pH range of 5.4～7.2 with a cationic slope of ca. 19～20 mV/concentration decade. No significant differences were found between electrodes with platinum, gold or silver as substrate metal or electrodes made with the ion-association complex of streptomycin silicotungstate, phosphotungstate, dicyclohexylnaphthalenesulfonate or dipicrylaminate. The new-type sensitive electrode has the advantage of fast response, stability and simplicity in construction. Direct potentiometric determination of 0.437～7.51 mg/ml streptomycin sulfate showed an average recovery of 96.6～99.1% and mean standard deviation of 4.7～5.9%. However, selectivity of the streptomycin ion-sensitive electrode is poor.