Because feed-grade urea is unstable, it is formulated (usually pelleted) to prevent degradation to NH 3. Biuret is a compound formed by heating urea to 180° C. When biuret is treated with dilute copper sulfate in alkaline condition, a purple colored compound is formed. Application of urea and biuret on oranges resulted in damaged leaves, where the apical portion of the leaf was the most sensitive to biuret (see photo). (1, 2, and 3) Biuret is a product of heating urea to about 180 degrees Celsius. Keita Sakakibara, Yoshihito Moriki, Yoshinobu Tsujii. The peptide bonds in Biuret give a positive result for the test hence the reagent is named so. The most common sources of NPN in feeds are urea, urea phosphate, ammonia (anhydrous), and salts such as monoammonium and diammonium phosphate. Biuret is not hygroscopic and is superior to urea-based products for all applications where supplemental NPN is required, including free-choice minerals, blocks and tubs, range cubes, conventional rations and liquid feed applications. Hyponasty, frayed leaf margins, and interveinal leaf chlorosis in immature leaves were symptoms associated with this injury. Biuret, a less toxic source of NPN, is being used less frequently than in the past. High heat is normal during urea manufacturing. Urea breaks down in the soil to give ammonium. Biuret test Principle of Biuret test: Biuret test is a general test for compounds having a peptide bond. This article is cited by 32 publications. This method also applies to the determination of biuret content in urea containing fertilizer with the results published in the J. AOAC in 2014 [5]. The unique nature of biuret makes it easy to include in ruminant diets while lowering cost of production. Biuret is a compound formed by heating urea at 1800 which results in the condensation of 2 molecules of urea. urea and biuret on oranges resulted in damaged leaves, where the apical portion of the leaf was the most sensitive to biuret (see photo). If in alkaline condition, biuret is treated using diluted copper sulfate, the color changes to purple. The ammonium is taken up by the plant. Therefore, it has a low transportation costs per unit of nitrogen nutrient. Hence, it is used to identify proteins in a particular sample, specifically biological fluids. Following foliar application of urea containing 0.5% biuret to potatoes, visual symptoms of yellow leaves, upward leaf rolling, and necrotic leaf margins have been noted. Biuret was toxic to germinating seeds and caused injury to developing corn seedlings. Biuret content is typically around 0.3 percent, although urea of foreign origin appears to be higher. The most common impurity of synthetic urea is biuret, which impairs plant growth. https://www.researchgate.net/publication/225205966_Biuret_in_urea_fertilizer Preparation of High-Performance Polyethylene Composite Materials Reinforced with Cellulose Nanofiber: Simultaneous Nanofibrillation of Wood Pulp Fibers during Melt-Compounding Using Urea and Diblock Copolymer Dispersant. If heat exceeds 200 degrees Fahrenheit, there’s a slight conversion of urea to biuret, but this takes place only during the manufacturing process. Urea has the highest nitrogen content of all solid nitrogenous fertilizers in common use. The biuret concentration determined for the unknown urea sample was found to be 0.20% (blue line). It is considered as a general test for compounds (proteins and peptides) having two or more peptide (CO-NH) bonds. Crystalline urea did not cause this injury to developing corn seedlings. These yellow leaves never regained their nor-mal color, although the new fl ush of growth appeared normal. The repeatability of the obtained result was verified after determining the biuret concentration of the synthetic standard described earlier (red lines).