For many years the level or protein in foodstuffs including meat, dairy and cereals has been carried out using the Kjeldahl method. This involves conversion of any nitrogenous compounds to ammonia by boiling the sample of food in concentrated sulfuric acid followed by addition of excess base. The ammonia is then distilled and collected in a suitable receiving solution followed by volumetric determination of the ammonia content by titration. The result in % by weight nitrogen is multiplied by a pre-determined factor to give the protein level in the analysed food. In 2008 a serious problems arose with dairy products in China due the adulteration with the nitrogen containing compound melamine. This at first went undetected, despite analysis of the dairy products using the Kjeldahl method, and there were a number of fatalities.
(a) Why is determination of nitrogen by the Kjeldahl method insufficient for the detection of melamine adulteration of diary products?
(b) provide the full reference for a recent research paper (2008 or later) that describes a new approach to the determination of melamine in diary products.
b]3. The Attempt at a Solution [/b]
Scientists have found that the Kjeldahl method does not distinguish melamine and other false nitrogen compounds from real protein. This is why the Kjedahl method could not be used sufficiently on adulterated dairy products. Is this correct????