Arginine (Arg) is an essential amino acid in the human body and can also be absorbed in food. Natural arginine is L-type, which is alkaline and easily reacts with acids to form salts. Arginine is an intermediate metabolite in the ornithine cycle, which can promote the conversion of ammonia into urea, thereby reducing blood ammonia content.Arginine generates urea under the action of enzymes, and urea can complex with oxime reagents under strong acidic conditions by boiling. The complex has a maximum absorption peak at 520 nm, and the arginine content can be calculated by measuring the OD value at 450 nm