基于中红外光谱检测牛奶中掺杂的尿素

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A1464的比值A1 ...

Adulteration detection of urea in milk by mid-infrared spectroscopy

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 x 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 comparisons of the differences were carried out. The absorption peak area (A1 562) 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 A1 562/A1 464 and urea concentration in milk. The results show that the A1 562/A1 464 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.