Improved Procedure for the Colorimetric Determination of Sulfamethazine in Feeds Containing Aureo SP-250®
Abstract The procedure provided by the manufacturer for the colorimetric determination of sulfamethazine in feeds uses a hot alkaline extraction. This extract is difficult to handle because many feeds form a gel and solubilized protein when heated in the presence of an alkaline solution. Centrifugation does not readily separate these solids. An extraction method utilizing a cold alkaline extraction and a double centrifugation has been developed which yields an extract that can be readily carried through the remaining steps of the analysis. Average recoveries were 104% at the 0.01% level and 106% at the 0.05% level of sulfamethazine. In addition, a separate study was conducted to determine whether penicillin or aureomycin interfere with the analysis for sulfamethazine. The data indicate that there is no interference.