title: New microbiological method for determining spectinomycin in pelleted and meal feeds using trifluoroacetic acid as primary extractant.
abstract: A new microbiological method, identified as the spectinomycin trifluoroacetic (SPE-TFA) method, was compared with the current AOAC method for analyzing spectinomycin in meal and pelleted feeds fortified with LS-20 premix. Feeds containing 3 concentrations of drugs and a zero level were tested in a correlation study. The data showed no significant differences in the percent of theory assayed between meal and pelleted samples using the SPE-TFA method, but the percent of theory found using the AOAC method was significantly lower for the pelleted samples than for the meal samples. The within-sample variation of the AOAC assay was also not the same for all samples; the SPE-TFA assay variation was relatively constant for all samples. The SPE-TFA method produced an overall average recovery of 98% with a range of 89-109% compared with an 85% recovery ranging from 64 to 102% for the AOAC method. In addition to producing better recoveries, the SPE-TFA method features a more sensitive response line, and final test solutions have viscosities and clarity more comparable to the standard solutions than those produced by the current AOAC method.
authors.affiliation: Upjohn Co., Kalamazoo, MI 49001.
authors.forename: G L
authors.initials: GL
authors.lastname: Stahl
authors.forename: M J
authors.initials: MJ
authors.lastname: Zaya
authors.forename: J B
authors.initials: JB
authors.lastname: Paulissen
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D001681:Biological Assay; D004926:Escherichia coli / Q000187:drug effects; D007202:Indicators and Reagents; D008034:Lincomycin / Q000032:analysis; D000198:Spectinomycin / Q000032:analysis* / Q000494:pharmacology; D014269:Trifluoroacetic Acid
chemical_list: D007202:Indicators and Reagents; D000198:Spectinomycin; D008034:Lincomycin; D014269:Trifluoroacetic Acid