Validation of an analytical method for the determination of spiramycin, virginiamycin and tylosin in feeding-stuffs by thin-layer chromatography and bio-autography.
An inter-laboratory validation was carried out to determine the performance characteristics of an analytical method based on thin-layer chromatography (TLC) coupled to microbiological detection (bio-autography) for screening feed samples for the presence of spiramycin, tylosin and virginiamycin. Twenty-four samples including blank samples and samples with concentrations of the target analytes ranging between 1 and 5 mg kg(-1) (expressed in microbiological activity) were analysed by seven laboratories participating in the study. The required detection limit was 1 mg kg(-1) (expressed in microbiological activity). For spiramycin, acceptable values for the sensitivity (at least 95%) indicating the rate of correct positive results were obtained for samples containing this substance at or above 2 mg kg(-1), whereas at 1 mg kg(-1), the sensitivity rate dropped to about 70%. Therefore, it was concluded that the detection limit was 2 mg kg(-1). For tylosin and virginiamycin, acceptable values of the sensitivity were obtained for all concentrations including 1 mg kg(-1). Therefore, the method fulfils the criterion regarding the required sensitivity at the target detection limit for tylosin and virginiamycin.
Vincent
Ursula
U
European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Food Safety & Quality Unit, Retieseweg, B-2440 Geel, Belgium.
Gizzi
Gisele
G
von Holst
Christoph
C
De Jong
Jacob
J
Michard
Jacques
J
D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis*; D002417:Cattle; D002855:Chromatography, Thin Layer / Q000379:methods; D005188:False Negative Reactions; D005189:False Positive Reactions; D011200:Poultry; D015203:Reproducibility of Results; D015572:Spiramycin / Q000032:analysis*; D013552:Swine; D015645:Tylosin / Q000032:analysis*; D014769:Virginiamycin / Q000032:analysis*
D000900:Anti-Bacterial Agents; D014769:Virginiamycin; D015572:Spiramycin; D015645:Tylosin