title: Rapid automated turbidimetric assay for chlortetracycline hydrochloride, using Leuconostoc mesenteroides as the test organism.
abstract: A rapid turbidimetric assay has been developed for chlortetracycline hydrochloride (CTC-HCl) in finished animal feeds and feed supplements, using Leuconostoc mesenteroides as the test organism. Two modifications are presented: The incubation period of modification 1 is 2.5 hr and the sensitivity of the assay is 0.03 microgram CTC-HCl/assay tube. Modification 2 has a sensitivty of 0.01 microgram CTC-HCl/assay tube and requires an incubation period of 3.5 hr. For 21 feed formulations, the turbidimetric method recovered 95.7% of label claim. Recoveries of CTC-HCl standards from the same feeds ranged from 93.4 to 134% with a mean of 103%. The relative standard deviation among day-to-day duplicates is 3.50% for the faster modification and 1.63% for the more sensitive modification.
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D001681:Biological Assay; D002751:Chlortetracycline / Q000032:analysis*; D007934:Leuconostoc / Q000254:growth & development; D009391:Nephelometry and Turbidimetry
chemical_list: D002751:Chlortetracycline