Selective and sensitive determination of tetracyclines by HPLC with chemiluminescence detection based on a cerium(IV)‐methoxylated cypridina luciferin analogue system

A novel approach for the simultaneous and selective analysis of chlortetracycline, doxycycline, 4‐epichlortetracycline, oxytetracycline, metacycline, and tetracycline by high‐performance liquid chromatography coupled with sensitive post‐column chemiluminescence reaction was set up. Six tetracyclines were separated through a simple and effective isocratic procedure using a mixture of acetonitrile and 3.5 mM methanesulfonic acid. After that, intensive chemiluminescence signals were produced by the reaction between cerium(IV) and methoxylated cypridina luciferin analogues system in the presence of tetracyclines. Under the appropriate experimental conditions, the developed method was evaluated by testing of linearity, limits of detection, precision, and accuracy. The limit of detection was from 2 to 10 nM and relative standard deviation of intraday precision was below 9%. The developed high‐performance liquid chromatography with chemiluminescence method has been performed for the with trace analysis of tetracycline antibiotic residues in milk samples with satisfactory results.