Automated photometric microbiological assay for monensin in poultry rations
Kavanagh, F.W.; Willis, M.
Journal - Association of Official Analytical Chemists 55(1): 114-118
1972
ISSN/ISBN: 0004-5756 PMID: 4199818 Document Number: 50747
A new photometric microbiological assay is described for the coccidiostat monensin in poultry feeds and premixes. The crucial steps in the assay are performed by an automated system. Samples are extracted with acetone and diluted in 50% aqueous acetone to appropriate levels for assay by Streptococcus faecalis ATCC 8043. A special pH 5.2 medium, low in potassium, and polysorbate 80 are used to obtain maximum sensitivity without interference. The range of applicability of the standard curve is 0.10–0.4 μg monensin/ml sample. The assay is free from bias. A relative standard deviation of 1.7% was obtained when 10 feed samples were extracted and assayed 5 times each.