Abstract
The fluorometric procedure for chlortetracycline in mixed feeds is based upon the degradation of chlortetracycline in alkaline solution to isochlortetracycline. The fluorescence of the isochlortetracycline is directly proportional to the concentration of chlortetracycline present prior to alkaline degradation. Chlortetracycline is extracted from mixed feeds with an acidmethanol solvent system, separated from the feed extract by adsorption on a Dowex 50 ion exchange resin, and eluted from the resin by ammonium hydroxide after conversion to isochlortetracycline. The isochlortetracycline is measured fluorometrically. Recoveries from known feeds are generally greater than 90% and agreements with microbiological assays are very close.
X-ray fluorescence determination of trace gold in an ion-exchange resin