Preliminary assays to elucidate the structure of oxytetracycline's degradation products in sediments - Determination of natural tetracyclines by high-performance liquid chromatography-fast atom bombardment mass spectrometry

A very specific high-performance liquid chromatography-mass spectrometric m ethod for the determination of natural tetracyclines was developed in order to characterise the degradation products of oxytetracycline in sediments. First, extraction used a clean up step with a Bond Elut Certify(R) LRC cart ridge. A 3 mum Spherisorb(R) ODS1 column was then used with a methanol, ace tonitrile and oxalic acid mobile phase gradient. Chromatographic resolution in these conditions was 3.31 between oxytetracycline and tetracycline. Two liquid chromatography-mass spectrometry methodologies based on a particle beam and a frit fast atom bombardment interface were developed. In the firs t approach, ionisation was performed in the negative chemical mode using me thane as reacting gas. In the other case, glycerol-thioglycerol mixture was used as matrix to ensure good sensitivity. MS-MS experiment was performed to determinate oxytetracycline fragmentation pattern in the perspective of degradation product study. (C) 2000 Elsevier Science BN. All rights reserve d.