Usage of HPLC explained

Picture of a HPLC system

Several analytical methods for quantitative detection of melamine using High Performance Liquid Chromatography have been developed and proposed as it has been proven to be a widely accepted for the analysis of biological matrices, pharmaceutical preparations due to its high efficiency and good reproducibility. Thus, it can be used for quantitative detection of most other compounds and not only melamine, making it extremely useful in the food safety industry. 

It is suitable for a variety of complex food and environmental material, has high sensitivity, high specificity, short detection time, low cost and requires minimal sample preparation. In this case, an ion exchange chromatography is performed for separation of charged molecules. HPLC also allows for analysis of large number of samples without degradation in column performance. Low noise is observed which proves its effective clean-up procedure for complicated matrices. As such, it is a highly useful tool for real-time analysis of routine melamine contamination monitoring.

To add on to the above, melamine is non-volatile, able to dissolve in aqueous solvent and thermally unstable (degrades upon heating) which fulfils the HPLC sample criteria.

The UV detector also had a set optimal wavelength of 240nm which gives a satisfactory retention of melamine, good peak shape and high sensitivity.

It should be noted that liquid chromatography/mass spectrometry (LCMS), gas chromatography (GC) and gas chromatography/mass spectrophotometry (GCMS) and capillary electrophoresis can also be used to detect melamine in infant formula and milk-based products but most of the aforementioned methods require expensive, complicated instruments and time-consuming sample pre-treatment (e.g. derivatisation or extraction).

Reference:
>> Der Pharma Chemica, 2012. Identification and Determination of Melamine in Milk by High Performance 
Liquid Chromatography – UV Detector. [online] Available at: <http://derpharmachemica.com/vol4-iss2/DPC-2012-4-2-737-748.pdf> [Accessed 27 January 2013]

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