title: Automated determination of crude protein, phosphorus, calcium, iron, and magnesium in feeds by using stopped-flow analyzer.
abstract: Methods are described for determination of crude protein, phosphorus, calcium, iron, and magnesium in feeds, using an automated microprocessor-based stopped-flow analyzer. Crude protein is determined by a reaction-rate procedure based on the ammonia-sodium phenate-hypochloride Berthelot reaction. Phosphorus determination is based on a phosphomolybdenum blue reaction-rate method. o-Cresolphthalein complexone, ferrozine, and calmagite are used as colorimetric reagents for calcium, iron, and magnesium, respectively. The methods are precise with relative standard deviations less than 1%, rapid with analysis rates of 110-266 samples per hour, sensitive, and require less than 1 mL sample and reagent volumes. Results for feed samples are comparable with those obtained by official AOAC methods.
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001322:Autoanalysis; D002136:Calcium, Dietary / Q000032:analysis*; D002417:Cattle; D002645:Chickens; D004044:Dietary Proteins / Q000032:analysis*; D007501:Iron / Q000032:analysis*; D008274:Magnesium / Q000032:analysis*; D008832:Microchemistry; D010758:Phosphorus / Q000032:analysis*; D013552:Swine
chemical_list: D002136:Calcium, Dietary; D004044:Dietary Proteins; D010758:Phosphorus; D007501:Iron; D008274:Magnesium