The Study Of Methods For Rapid Detecting Banned Additives In Milk

With the improvement of human living standards and health awareness, the status of dairy products in people’s life becomes more and more important. Since milk is the raw materials of all dairy products and a large number of dairy products have been used by people in recent years, milk quality problems have caused more and more attention. Since the "sanlu milk powder" contaminated with melamine in2008, the cases of dairy products containing banned additives have been reported frequently. This shows that there is a problem of milk quality tests.At present, the chemical analysis methods, such as high performance liquid chromatography, liquid chromatography-mass spectrometry and so on, which used to detect banned additives, have high detection precision. But they need to consume organic solvent, consume more time and require special operations personnel. So it is only suitable for used in laboratory, not suitable for a large number of samples on-site rapid detection in real time.Fortunately, the spectrum detection technology has gradually to be the concern of people in recent years. This method is rapid, no pollution. So it can achieve rapidly and accurately to detect. However, the spectrum analyzer is so large size, expensive, difficult to operation and maintenance, which make it not suitable for field real-time operation and mobile detection. Considering the large gaps of scale, capital, and management existed in our country’s milk stations, the spectrum analyzer cannot be widely available.In this paper, take melamine as an example, we mainly studied several spectrum detection methods for detecting banned additive in milk. We designed and fabricated an improved system device called’automatic closed-loop detection and control system’. The system device can be effectively used in milk production line or milk purchasing station, which provide a feasible solution and a prototype for ensuring product safety and promoting higher productivity of dairy enterprise. Thus, the system device we designed has important reference value and practical value. The main contents include:1. The principle, characteristics and applications of Raman spectroscopy were discussed and the method that using Raman spectrum technology to detect melamine in milk was researched. The technology which based on the surface enhanced Raman spectroscopy is not suitable for on-site rapid detection in real time since it need complicated sample pretreatment. Therefore, the method was not further studied.2. The principle, characteristics and applications of fluorescence spectroscopy were discussed and the method that using fluorescence spectrum technology to detect melamine in milk was researched. The experimental result shows that the fluorescence intensity first increases and then decreases with the increasing concentration of melamine in milk. Based on this point, we designed a simple detection device which combined the photoelectric technology with computer technology.3. The principle, characteristics and applications of near-infrared spectroscopy were discussed and the method that using near-infrared spectrum technology to detect melamine in milk was researched. And using near-infrared spectrum technology, we designed and fabricated a novel system device which combined photovoltaic technology with computer technology. The device can quickly detect whether the milk containing melamine in real-time and accurately show the concentration of melamine.4. According to the market survey results and the practical application, we further designed and fabricated an applied system device. The system not only can detect whether milk contained banned additives. It also can be real-time monitoring of different dairy products corresponding water content or pure milk content. Therefore, based on the previous study, we studied the detection of water content in milk. It mainly discussed that an optical fiber refractive index sensor was fabricated and its spectral character was investigated. And we researched the method to detect the water content by using the refractive index sensor and developed a detecting system device.