基于中红外光谱检测牛奶中掺杂的尿素

Adulteration Detection of Urea in Milk by Mid-Infrared Spectroscopy

采用中红外光谱技术对牛奶中掺杂尿素目标物进行检测。配置含有尿素浓度范围为1～18 g.L-1之间18个牛奶样品,分别研究了纯牛奶和掺杂尿素牛奶的红外光谱特性,并进行了对比分析。利用尿素1 562 cm-1处酰胺Ⅲ带C O伸缩振动吸收峰面积A1 562与1 464 cm-1处C—N伸缩振动吸收峰面积A1 464的比值A1 562/A1 464对牛奶中尿素浓度进行线性拟合,研究结果表明A1 562/A1 464与牛奶中含有尿素浓度具有一定的线性关系,其相关系数达到0.96以上。该研究对提高乳制品的质量,保护消费者利益具有重要的社会意义和应用前景。

In the present study, a technique of mid infrared spectroscopy for detection of urea in milk was put forward. Eighteen adulterated milk samples with added different content of urea （1~18 g · L^-1） were prepared. The mid-infrared spectra of these milk samples were measured. The infrared characteristics of pure milk and adulterated milk were studied, and analysis and com- parisons of the differences were carried out. The absorption peak area （A1 s62） of 1 562 cm^-1 , which was assigned to the C--N stretching vibration for urea, and the absorption peak area （A1 464） of 1 464 cm 1, which was assigned to the C=O stretching vibration for amide Ⅲ, were calculated by origin. Linear fitting of relation was made between A1462/A1 464 and urea concentra- tion in milk. The results show that the A1462/A1464 is linear with urea concentration in milk, with a regression coefficient of 0.96. The study is important to improving quality of dairy products and protecting the benefit of consumers, and takes on crucial social significance and application prospect.