A simple and sensltlve method for the determmatlon of gentanncm m calf tissues (muscle, hver, Rodney and fat) based on bqmd chromatography (LC) IS descriied A 5% (w/v) tnchloroacetlc acid solutron was used to precipitate protems Afte.r centnfugation of the sample, the pH and IOOIC strength were adjusted for further purdicatron by hqmd-sohd Ion-exchange extractron usmg CM-Sephadex gel A lUCkpI abquot of the eluate from the loo-exchange cartridge On 0 05 A4 NaOH) was rmected on to the LC column after abuatment of the pH and counter loo concentration The chromatography consisted of an loo-pamng system rvlth a mobile phase contammg camphorsulphonate as the counter loo, a reversed-phase column (LtChrospher 100 RP-18 end-capped) and postcolunm denvatlzation mth o-phthalaldehyde and 2-mercaptoethanol followed by fluormetnc detection The three major components of gentanucm were eluted as a smgle peak Recoveries ranged from 68 to 98% m tissue samples fortlfied wth gentanucm at 0 OS-3 2 pg g-l levels The hnnt of quantlficatlon was 50 ng g-' IO muscle and fat and 100 ng g -I m hver and lodney Keywords Llqmd chromatography, AntIbloWs, Calf tissues, Gentanucm Antlblotlcs are widely used to treat serious mfectlons m livestock and to prevent disease These practices nnply that drug residues may persist m edible tissues derwed from treated ammals Such residues, tf ammals have been heavdy dosed, may be a nsk to the consumer Consequently, Hrlthdrawal periods must be determmed Ammoglycosldes are a therapeutlcally Impor-Correspondence to A. Nlcolas, Laboratolre de Chlrme Analytlque, URA CNRS 597, FacultC des sciences Phannaceutlques et Blolomques, B P 403,540Ol Nancy Cedex (France) tant class of antlblotxs but possess signlfrcant potential for toxzlty However, gentanucm, together wth streptomycm, dlhydrostreptomycm and neomycm have been approved for vetermary use m food-producmg ammals [l] Gentamlcm, a m&l-component ammoglycoslde antlblotlc, was first isolated by Wemstem et al [2] from Mcromorwspora pwpurea and was mtroduced as a therapeutic agent m 1969 It has a broad spectrum of actlvltles against both Gram-positwe and Gram-negative bactena It is composed of three major components, C,, C, and Cla, which have sun&x antlbactenal properties [3]