“…One way of achieving this is to decrease their consumption, and this requires monitoring methods for tetracycline residues in samples such as blood serum, urine, milk, egg, and animal tissues . Tetracycline has been previously determined in blood serum by using liquid chromatography, , high-performance liquid chromatography, − capillary electrophoresis, stopped-flow mixing, and differential-pulse polarography . Very recently, methods based on titrimetry, recombinant Escherichia coli sensors, and electrospray ionization mass spectrometry have also been described for the determination of tetracyclines.…”