Enzyme-linked immunosorbent assays of fluoroquinolones with selective and group specificities

Two ciprofloxacin (CF)-bovine serum albumin conjugates with oppositely orientated hapten and gemifloxacin (GF)-glucose oxidase synthesised by activated esters method, carbodiimide condensation and glutaraldehyde linking, respectively, were used as immunogens. A wide spectrum of immobilised antigens different in carrier, type of hapten (CF, GF, sparfloxacin), hapten load and conjugating method were prepared. Thirteen variants of competitive indirect enzyme-linked immunosorbent assay (ELISA) using three rabbit antisera and solid-phase conjugates were developed to detect fluoroquinolones (FQs). The immunoreagent combinations allowed to determine CF and GF selectively, to carry out the quantification of CF, enrofloxacin, norfloxacin, pefloxacin and lomefloxacin practically with equal efficacy. Under the conditions of group-specific ELISAs the immunochemical activity of 9-10 FQ representatives differed only 10-20 times. The possibility of efficient influence on ELISA specificity and sensitivity with especially selected immobilised antigens was demonstrated.