Tetracycline detection chromatographic methods

The usual method of detecting chromatographed tetracycline antibiotics involves fuming the paper with ammonia vapor and observing the yellow fluorescence under UV light. As little as 0.2-0.5 pg can be visualized by this technique. 

Spisso B, de Oliveira e Jesus A, et ah, Validation of a high performance liquid chromatographic method with fluorescence detection for the simultaneous determination of tetracycline residues in bovine milk, Anal. Chim. Acta 2007 581 108-117. 

An on-line concentration, isolation, and Hquid chromatographic separation method for the analysis of trace organics in natural waters has been described (63). Concentration and isolation are accompHshed with two precolumns connected in series the first acts as a filter for removal of interferences the second actually concentrates target solutes. The technique is appHcable even if no selective sorbent is available for the specific analyte of interest. Detection limits of less than 0.1 ppb were achieved for polar herbicides (qv) in the chlorotriazine and phenylurea classes. A novel method for deterrnination of tetracyclines in animal tissues and fluids was developed with sample extraction and cleanup based on tendency of tetracyclines to chelate with divalent metal ions (64). The metal chelate affinity precolumn was connected on-line to reversed-phase hplc column, and detection limits for several different tetracyclines in a variety of matrices were in the 10—50 ppb range. 

In Australia, the general antimicrobial screen is performed on kidney and is able to detect -lactam, aminoglycoside, tetracycline, and macrolide antimicrobials and to identify the class of antimicrobial compound present. Where the screen test identifies a class of compounds, confirmation and quantitation are done by the specific HPLC or gas chromatographic (GC) method appropriate for the class of antimicrobial. 

Following sample extraction and cleanup, tetracycline antibiotics may be separated by thin-layer or liquid chromatographic procedures, and quantified by spectrophotometric, fluorometric, or mass spectrometric detection systems. Direct spectrophotometric and capillary electrophoretic methods have also been described (Table 29.8). 

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