Mini-column screening assay for tetracyclines in chicken

A simple, rapid, reliable and economical mini-column (MC) method for the detection of tetracyclines (TCs) residues in chicken meat was developed. The method employs a commonly available Pasteur pipette which is tightly packed with silica gel and anhydrous sodium sulfate. Clean-up and detection of illegal levels can be achieved on the same column. Viewing the developed MC under an ultraviolet lamp revealed that TCs can be detected as a compact golden yellow fluorescent band at the junction between the anhydrous sodium sulfate and silica gel layers. Comparing the yellow band of control extracts with those fortified (100 ng ml(-1)) showed no overlap between analyte and impurities. The limit of detection (LOD) of the MC assay was 1 ng, indicating that the chicken sample containing 10 µg TCs kg(-1) sample could be easily detected. Moreover, the intensity of the yellow band increased whenever TCs levels in the extract increased. Evaluation utility of the method with blind samples as controls or samples fortified with total TCs at various levels indicated that the total blank and spiked samples at levels equal or below the permissible limits were assessed as accepted. The method can provide an alternative to microbial screening assays and could be used as an effective pre-screening technique in public health laboratories.