Liquid chromatographic determination of ivermectin in feed.
An analytical method for determining ivermectin in feed at 0.50-3 ppm is presented. The method is based on liquid chromatographic measurement after sample preparation by adsorption chromatography on alumina and solid-phase extraction. Two complete, final, finished medicated feeds and the corresponding control feeds used in their preparation were analyzed. Recoveries from feeds fortified at 50-150% of the 2 ppm ivermectin use concentration also were determined. Mean recoveries from replicate analyses ranged from 90 to 100%, and coefficients of variation (CVs) were less than 4.5%. No significant interferences were found in control feeds. The pooled distribution of individual analytical results (n = 100) gave a mean recovery of 100%, a recovery range of 90-111%, and an overall CV of 5.5%. Resolution of the total variance into its 2 components gave a within-laboratory CV of 4.1% and a between-laboratory CV of 3.4%. There was no significant difference in recoveries among laboratories, days, concentrations, and feed base or between fortified and medicated feeds (P > 0.2).
Merck Research Laboratories, West Point, PA 19486-004, USA.
S J
SJ
Doherty
A
A
Fox
D W
DW
Fink
D000821:Animal Feed / Q000032:analysis*; D000871:Anthelmintics / Q000032:analysis*; D002853:Chromatography, Liquid; D007202:Indicators and Reagents; D007559:Ivermectin / Q000032:analysis*; D011786:Quality Control; D012015:Reference Standards; D012996:Solutions
D000871:Anthelmintics; D007202:Indicators and Reagents; D012996:Solutions; D007559:Ivermectin