Wai+Man's+Log

=Research Project=

01/10/2009
Decided on research topic: melamine milk crisis in China Still have to decide on which area to write about. Possibly melamine testing in food products, or melamine's toxicity in the human body.

01/10/2009
Decided on research topic title: Toxicity of Melamine and the determination of Melamine in food product

Homework Assignment 2:
Link to the publisher's site: []
 * [Full Marks JCB]**

Melamine contamination, Yu-Chang Tyan, Ming-Hui Yang, Shiang-Bin Jong, Chinh-Kuang Wang, Jentaie Shiea. (Source in PDF)

Abstract and Introduction:
A brief introduction to the melamine crisis in China, and the cause and outcome of the crisis. It also listed different instrumental analysis methods detecting melamine that will be described in the article.

Discussion:
It described what melamine is by giving the chemical formula, and the founder of melamine. The method of synthesizing melamine, the by product/metabolite of melamine is also given. The uses of melamine were described: melamine is a resin and the property of it is discussed. The solubility of melamine is given, and stating that the solubility of melamine is very low. The reason for the adulteration of melamine is given. Melamine has very similar characteristics compared to amino acids (because of the nitrogen), while there is an assay that test the protein content in food products (Kjeldahl reaction), the reaction only quantifies the presence of nitrogen, which is in amino acids. The manufacturer in China used melamine to adulterate the food products, so the food product can show a high reading of protein. At first the adulteration is only on pet food, which causes hundreds of pet’s death. The melamine contamination in milk also caused death of infants and babies, although the toxicity of melamine is reported as low. After testing it is shown that a single oral exposure to a mixture of melamine and its derivative can cause renal failure and form crystals in the kidney. The melamine contamination in milk and milk product started because at that time milk was not tested for the melamine content; which is because regulator did not suspect melamine was used to increase the protein reading. Melamine is not a natural product and it is not allowed to be added in food (although it is allowed to be used as a food-contact substance). The toxicity of melamine was tested on animal and it showed a list on symptoms including kidney and bladder crystal. The test also indicated that melamine could be a carcinogen in male, while the male rat that was exposed to melamine for a prolonged period of time and resulted in urinary bladder tumor.

The reason for melamine’s toxicity is hypothesized that since melamine and its derivative, cyanurate acid is insoluble in water; the gastrointestinal tract absorbs the two compounds and distribute it in the kidney, which later forms crystal. When the test is performed on cats, it has shown that just melamine or cyanurate acid does not cause kidney failures in cat, but the combination of both causes acute renal failure. The action of the safety authority from different regions of the world (The United States, Europe, and New Zealand) was discussed. The US FDA and the New Zealand food safety authority decided to test all the dairy products for melamine and reported a new tolerable daily intake for adults and infants, whereas the European food safety authority decided to ban all milk products from China.

Different detection methods of melamine and their general procedure were discussed. For the detection of melamine and cyanurate acid, HPLC with UV detection, GCMS, and Raman spectroscopy can be used. A table was shown listing all the different instruments and method that can be used for detection on different food samples. The analysis using GCMS and LCMS is common however it requires a long sample preparation due to the fact that food is a complex matrix. The new method, known as the isotope dilution method, was then discussed. By using this new method the matrix effect in different samples can be prevented. Another new method is using the SERS coupled with gold nanosubstrates. SERS is a brand of Raman spectroscopy that measures molecular vibration by light scattering. There is also the ELISA test kit that was developed to test for melamine in food product. All these methods are yields good repeatability and sensitivity.

Conclusion:
The US FDA described the health risk when melamine is consumed. When melamine is coupled with other analogue such as cyanuric acid it can be fatal when consumed, since it forms crystals in the kidneys. New regulation and testing methods should be establish to prevent melamine contamination.

Homework Assignment 3:
Properties of Melamine
 * [Full Marks - JCB]**

1. Boiling Point: --557.5 °C at 760 mmHg (Predicted) [|ChemSpider] --sub [|CRC] (Search for Melamine, under interactive table) --Sublime [|Wikipedia] --557.5°Cat760mmHg [|LookChem] --sublime [|MSDS]

2. Melting Point: --ca 350° dec. [|Alfa Aesar] --345 dec [|CRC] (Search for Melamine, under interactive table) -->300 °C(lit.) [|Sigma Aldrich] --345 °C, 618 K, 653 °F (decomposition) [|Wikipedia] --345°C [|MSDS]

3. Density: --1.66g/cm3 [|LookChem] --1.573 [|Alfa Aesar] --1.66 g/cm3 [|ChemSpider] --1.57 g/cm3 [|MSDS] --1.573 g/cm3[|Chemical Book]

4. Flash Point: --325.3°C [|LookChem] --325.3 °C (Predicted) [|ChemSpider] -->110°C [|Chemical Book] -->280°C [|Acros] --325°C [|WolframAlpha]

5. Solubility in water: --3 g/L (20 ºC) [|Chemical Book] --Slight [|MSDS] --3.240 g/l (20 °C) [|Wikipedia] --Slightly [|Chemicalland21] --3.1 g/l at 20 °C [|Inchem] (Search Melamine under Chemical name)

6. Stability --Stable under ordinary condition [|Chemicalland21] --Stable. Incompatible with strong acids, strong oxidizing agents. Nonflammable. [|Chemical Book] --Stable. Incompatible with strong acids, strong oxidizing agents. Nonflammable. [|MSDS] --Melamine is a stable, non-hazardous product. [|DSM] --The product (Melamine) is stable. [|Sciencelab] (MSDS sheet link to the PDF)

29/11/2009 - Fixed [WM]

27/11/2009
Research Project created on my page.