含有甲醛尿素聚合塑膠摻雜物的飼料，魚粉，乳粉，麥片粉，玉米粉，豆粉，骨粉等等的檢品5-10克於500-1000 ml蒸餾瓶中，加入約100 ml稀硫酸溶液(1→5)振搖均勻，再以約50 ml水洗下瓶壁殘留物，蒸餾出約二分之一餾液，取5 ml加5 ml變色酸試液(Chromotropic Acid T.S.)於60-80℃水浴加熱20-30分鐘，如溶液呈紫紅色，則可檢測出甲醛，其敏感性可測得函0.1％甲醛尿素聚合塑膠的添加物，以防止不法商人掺假危害家畜，魚類，建立一便捷可行之檢驗方法。 A simple method is propsed for the determination of formalin-urea polymers in animal feeds. Place about 5-10g sample containing formalin-urea polymers into a 500-1000 ml flask and add 100 ml sulfuric acid solution( 1→5 ), then shake well and distil. After equivalent volume of the distillate and chromotropic acid T.S. heat on 60-80℃ water bath for 20-30 minutes, it will produce a violet color. This method is sensitive to concentration 0.05-0.1% of formalin-urea polymers in the animal feeds.
