Chromatographic Techniques for Melamine

Melamine is an industrial chemical with an organic base and is used for the manufacture of plastics, fabric glues and housewares and is also a component in pigment yellow 50, which is used as colorant in plastics and inks. The content of nitrogen is very high in melamine, forming approximately 66 percent of its mass value. Due to high nitrogen content, some food manufacturers use it as an adulterating agent in protein-rich foods like infant milk formula, cookies and candies. They use melamine to substitute the protein content in the food as it is not easily detected by the quality control checks conducted on them. This problem is very grave as it will directly affect the well-being of the masses and hence the international food manufacturing industry has taken a serious note of this issue. They are researching and evolving various analytical tests to determine the presence of melamine in food products.

LC-MS-MS Method

• The methods which are used for detecting melamine contamination should be sensitive enough to detect negligible quantities of contaminant present in the food products. One of the most popular methods of detecting melamine contamination in complex samples of edible products is liquid chromatography together with mass spectrometry, or LC-MS-MS method. The chromatography analysis of presence of melamine involves molecular separations using analytical techniques. Highly selective and sensitive detection of molecular and trace compounds is possible using this method. This method is very precise and is suitable for selective reaction monitoring performance. The chromatographic technique which may be either preparative or analytical is a set of laboratory techniques for separating mixtures for their further analysis or purification.

Mass Spectrometry

• Mass spectrometry is used in combination with the electrospray ionization method to provide a direct and quick analysis of samples having matrices that are complex in nature. In this procedure, the liquid sample is ionized directly under controlled conditions in its own solution. These days, ultrasound is also used for extractive electrospray ionization procedure. EESI-MS, or ultrasound assisted extractive electrospray ionization mass spectrometry, has been specially developed for rapidly detecting the presence of melamine in food samples that have not been treated. In this procedure, the ultrasound is used to nebulize the melamine contaminated fluid or liquid into a fine spray which is then ionized by extractive electrospray ionization. The sample is also analyzed for a duration of 30 seconds by the tandem mass spectrometry method. Using this procedure, the presence of melamine per gram of milk can be detected in nanograms.

Triple Quadruple Liquid Chromatography

• Though this method of triple quadruple liquid chromatography is very effective in determining the extent of presence of melamine in the food product, it requires a lot of time to conduct this procedure. This procedure is also very complex in nature but is very popular owing to the accuracy of results.