AOAC RI ERP E-Book - DS DF

AOAC RESEARCH INSTITUTE AOAC OFFICIAL METHODS OF ANALYSIS (OMA)

OMAMAN-13: Determination Of Dietary Starch In Animal Feeds And Pet Food By An Enzymatic- Colorimetric Method Collaborative Study* Study Director: Mary Beth Hall, U. S. Department of Agriculture – Agricultural Research Service, U.S. Dairy Forage Research Center, 1925 Linden Drive, Madison, WI 53706, USA

Precision

ER 1 ER 2

Average RSDr 3.5% RSDr % = 1.23 - 8.61%

ER 3 Acceptable. Soybean meal was the highest but this was likely due to a possible lower degree of sample homogeneity. ER 4 See method collaborative study report. ER 5 2-3% most samples; >8% Alfalfa pellets (low level @ ~1%); ~6% Dry Dog Kibble; 5% Soybean Meal (low level @~1%) ER 6 RSD(r) varies from 1.2 - 8.6 %, and is generally below 5% which I would generally regard as acceptable. ER 7 good ER 8 Good

Reproducibility

ER 1 ER 2

Average RSDR 6.1% RSDR% = 3.87 - 11.16%

ER 3 Acceptable. Soybean meal was the highest but this was likely due to a possible lower degree of sample homogeneity. ER 4 See method collaborative study report. ER 5 4-6% most samples; ~10% for Alfalfa pellets and Soybean Meal ER 6 RSD(R) varies from 3.9- 11.2 %, and is generally below 6% which I would also consider acceptable. ER 7 good ER 8 Good

System Suitability

ER 1

Good systems suggested (Starch, sucrose, glucose)

ER 2 The use of corn starch as control sample to evaluative quantitative recovery in the assay. ER 3 see above ER 4 Definitely suitable for purpose ER 5 N/A ER 6 The use of enzymatic hydrolysis to convert starch to glucose, and the GOPOD assay to specifically assay the starch means the method is very selective. Potential interferences have been identified and suitable controls are mentioned. ER 7 good ER 8 Acceptable AOAC Research Institute ERP Use Only