Tetracycline Potentiometric Sensor Based on Cyclodextrin for Pharmaceuticals and Waste Water Analysis

In this work, the construction and performance evaluation of PVC membranes ion‐selective electrodes for the determination of tetracycline type antibiotics is described. Electrodes with the best responses were based on plastic membranes containing 31% (w/w) PVC, 68% (w/w) of dibutylphthalate as plasticizer and 1% (w/w) of β ‐cyclodextrin as ionophore. The electrodes were responsive over 6 months to tetracycline, oxytetracycline, doxycycline and chlortetracycline in glycine buffer solution (pH 2), in the dynamic range 2×10 −5 –10 −2 mol L −1 with a constant slope of about 55 mV/dec To enable large scale analysis reducing wastes as associated costs tubular shape electrodes were coupled to a sequential‐injection analysis system and its performance evaluated using pharmaceutical samples and waste waters from a treatment facility. The sample throughput of 51 samples h −1 was enabled by the system as well as results that favorably agree with those provided by chromatographic analysis.