COLLABORATIVE STUDY OF THE ANALYSIS OF TYLOSIN BY LIQUID-CHROMATOGRAPHY ON WIDE-PORE POLY(STYRENE-DIVINYLBENZENE)

A previously developed method for analysis of tylosin A and related su bstances by liquid chromatography using a wide-pore poly(styrene-divin ylbenzene) stationary phase was examined in a multicentre study involv ing 7 laboratories and 3 samples. The main component and the impuritie s were determined. An analysis of variance showed absence of consisten t laboratory bias and significant laboratory-sample interaction at the 1 % level. Estimates for the repeatability and reproducibility of the method, expressed as standard deviation (SD) of the result of the det ermination of tylosin A, were calculated to be 1.3 % and 1.6 % respect ively.