Quantitative determination of sulphamethazine and carbadox in animal feeds by paired ion high-performance liquid chromatography

Abstract

Carbadox and sulphamethazine can be determined quantitatively at the parts per million level in animal feeds with 100% recovery. The drugs are extracted with chloroform-methanol, vacuum filtered through Celite, then cleaned up by an aqueous sodium chloride-sodium hydroxide liquid-liquid extraction. The drugs are recovered by extraction from aqueous monobasic potassium phosphate with chloroform, the solvent is evaporated and the residue is diluted to volume with the high-performance liquid chromatography mobile phase 25% acetonitrile + 75%(0.5% acetic acid-0.05% octane-1-sulphonic acid). UV detection is at 254 nm.