Comparison of HgO and CuSO4 as digestion catalysts in manual Kjeldahl determination of crude protein in animal feeds: collaborative study.
The official AOAC manual Kjeldahl method for determining crude protein in animal feeds, 7.015, uses HgO as a catalyst in the digestion step. Because of environmental considerations, there is considerable interest in alternative catalysts. A collaborative study compares the official HgO-catalyzed method and an alternative using CuSO4. Fifty-four samples consisting of blind duplicates of closely matched pairs, representing a range of animal feed materials and 2 standard materials, were analyzed once by each method. Results were returned by 22 laboratories. Means and standard deviations between methods were comparable. The CuSO4-catalyzed method has been adopted official first action.
D000821:Animal Feed / Q000032:analysis*; D002384:Catalysis; D055598:Chemical Phenomena; D002621:Chemistry; D003300:Copper; D019327:Copper Sulfate; D004044:Dietary Proteins / Q000032:analysis*; D008239:Lysine / Q000032:analysis; D008628:Mercury; D017669:Mercury Compounds; D010087:Oxides
D004044:Dietary Proteins; D017669:Mercury Compounds; D010087:Oxides; D003300:Copper; D008628:Mercury; C019468:mercuric oxide; D008239:Lysine; D019327:Copper Sulfate