Microbiological Assay of Tetracycline with a Potentiometric CO2Gas Sensor

Abstract
A novel potentiometric method for the determination of the antibiotic tetracycline in pharmaceutical preparations is reported. The method is based on the inhibition of respiration of a suspension of Escherichia cole, which is measured with a potentiometric carbon dioxide sensor. The dose-response curve of carbon dioxide produced versus the logarithm of the tetracycline hydro-chloride concentration is linear from 33 to 167 μg/ml. Good agreement with the label claim was obtained in the assay of a pharmaceutical preparation of tetracycline hydrochloride.