HPLC DETERMINATION OF RESIDUES OF SPECTINOMYCIN IN VARIOUS TISSUE TYPES FROM HUSBANDRY ANIMALS

An HPLC method was developed for the determination of bacteriostatic a minocyclitol spectinomycin (SP) in animal tissue products. These produ cts included chicken eggs and edible fat, kidney, liver, muscle tissue s from calf, poultry, pig and sheep. Residues of SP were extracted fro m homogenized tissue and egg-derived material with 25 mM citrate of pH 4.0, trichloroacetic acid and dichloromethane. The extract was purifi ed and concentrated over a carboxylic acid-bonded solid-phase extracti on (SFE) column. The SPE-eluate was analysed by cation-exchange HPLC i nvolving a two-column Switching system, post-column derivatization and fluorescence detection. Spectinomycin could be successfully determine d at levels of 0.05 mg kg(-1) and higher. Recoveries from spiked tissu e material and from spiked egg material were in excess of 74% and did not show a concentration or tissue-type dependence. Precision of the e lution position and signal response was better than 2%. Matrix effects and interference from lincomycin were less than 7 and 2%, respectivel y, on the signal response. Spectinomycin was shown to be stable at -20 degrees C in combined egg yolk and white over a test period of 12 wee ks and in calf and sheep muscle tissue over a test period of 10 days. SP was, however, not stable at this temperature over a period of 12 mo nths in chicken muscle tissue. Incurred SP residues were successfully determined in kidney and muscle tissue at the injection site of pigs a dministered with two doses of 15 mg kg(-1) body weight SP with an inte rmittent withdrawal period of 15 days. Kidney showed higher concentrat ions and more persistent residues of SP than muscle tissue at the inje ction site.