Abdihakim Abdullahi: Analytical Problem; Mercury in Skin Supplies
Recently more and more products such as Diana and Lemon Herbal Whitening Cream have shown up in the markets with mercury levels well over the permitted federal limits, of less then one parts per million, of mercury. Some of these products have shown levels of 33,000 parts per million of mercury. With these products finding their way to shelves of stores through informal trade it is difficult to keep track of them. Therefore these products continue to circulate. Mercury is an extremely toxic element and exists in nature in many different types of forms and oxidation levels, with the most common being Mercury (II). Mercury in bleaching and cosmetic creams were introduced the early 1900 when it was discovered that Mercury was extremely effective in lightening dark spots and stubborn pigmentation but it also had a high remission rate. Nevertheless bleaching creams with high levels of Mercury was aggressively marketed to black people. In 1976 Mercury was banned in the EU when it was discovered that it had damaging side effects. The US banned the use of Mercury in cosmetic creams much later in 1990. The reason Mercury was banned was it proved to be very toxic and can absorb through the skin and cause neurological affects and can even poison and shut down certain organisms like the kidneys.
My hypothesis is the mercury in these products cause a lot of health issues especially pertaining to communities such as the Somali community in which these products keep showing up in.
1. Skin-Lightening Products Found to Contain Mercury: Minnesota Department of Health. http://www.health.state.mn.us/topics/skin/ (accessed September 19, 2011)
2. Lide, D. R., ed (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. pp. 4.125-4.126. ISBN 0-8493-0486-5
UV-Vis absorption spectrometry
As I mentioned before Mercury exist in many different forms like the organic mercury found in fish, methylmercury. However the Mercury found in most of these cosmetic creams is inorganic Mercury (II) usually mercuric chloride (HgCl2) or mercuric amidochloride (HgNH2Cl). Inorganic Mercury is soluble in alcohols so an ideal solvent would be ethanol because various types of inorganic Mercury (II) have shown UV-Vis absorption at wavelengths ranging from 200 nm to 600 nm with the average being about 260 nm, and ethanol has a lower wavelength limit of 220 nm so it is an ideal solvent. Mercury is considered a transition metal and the molar absorptivity of bands caused by d-d transitions are relatively low, roughly in the range of 5-500 M-1 -cm1.
Sekine, T., Ishii, T. Studies of the Liquid-Liquid Partition systems. VIII. The Solvent Extraction of Mercury (II) Chloride, Bromide, Iodide and Thiocyanate with Some Organic Solvents. Bulletin of the Chemical Society of Japan. 1970. 43. 2422-2429
Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.
Mercury Analysis in Environmental Samples by Cold Vapor Techniques. In: Encyclopedia of Analytical Chemistry. 2006.
Skoog , D, et al. Principles of Instrumental Analysis, 6th ed.; Brooks/Cole: Belmont, CA, 2007.
A problem thats actually very similar to mine is Chuxin Chen Analytical problem: comparative analysis of arbutin and tranexamic acid in skin whitening products. We both took an approach on cosmetics and however my approach is on a toxin found in some creams while Chuxin's is a comparative analysis between two different compounds to see which is more effective.
my analyte, Inorganic mercury, exist in many forms but the two that are most common in bleaching creams are either mercuric ammido chloride View image
and more likely mercuric chloride View image
the space filling model and the stick model of mercuric chloride are as follows View image View image
Reference for images:
I found all these images on Colombia Analytical Services (CAS) at their website; http://www.caslab.com/Mercuric_chloride_CAS_7487-94-7/
Standards for mercuric chloride could be purchased at the Sigma Aldrich website, http://www.sigmaaldrich.com/catalog/ProductDetail.do?lang=en&N4=203777|ALDRICH&N5=SEARCH_CONCAT_PNO|BRAND_KEY&F=SPEC&cm_sp=Customer_Favorites-_-Detail_Page-_-Text-203777, It sells for $99.40 the product number is 203777-50G. the CAS # is 0007487947 and since it is very toxin it must be shipped in a special poison packaging and the fee is incorporated in the price.