Analytical Presentation 1

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B Y : A B D I H A K I M A B D U L L A H I

C H E M 4 1 0 1

D E C E M B E R 9 , 2 0 1 1

Mercury In Skin Supplies


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Background

Mercury in bleaching and cosmetic creams were introduced inthe early 1900 when it was discovered that Mercury wasextremely effective in lightening dark spots and stubbornpigmentation but it also had a high remission rate.

Nevertheless bleaching creams with high levels of Mercury wasaggressively marketed to black people. In 1976 Mercury wasbanned in the EU when it was discovered that it had damagingside effects. The US banned the use of Mercury in cosmetic

creams much later in 1990.

Mercury was banned as it proved to be very toxic and couldabsorb readily through the skin causing neurological effects.


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Problem:Recently more and more products such as Diana and LemonHerbal Whitening Cream have shown up in the markets,through informal trade, with mercury levels well over thepermitted federal limits, of less then one parts per million, ofmercury. Some of these products have shown levels at 33,000parts per million of mercury.

Hypothesis:Mercury in said products cause a lot of health issues especiallypertaining to communities in which these products keepshowing up in.


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Experiment Overview

Separation: My analyte,inorganic mercury, is in a

very complex matrix(cosmetic cream) so the

first thing we have to dois separate the mercury.

Identify: Next we have to

identify the mercury,then quantify it.

A bottle of mercuric chloridewhich was classified as apoison.6


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Possible Detector techniques

Technique Advantages Disadvantages

UV-Vis Absorption Simple design, quicksample analyses and it isnondestructive to sample.

Requires frequentcalibration, stray light canalter results.

Atomic AbsorptionSpectroscopy

Simultaneous analyses ofdifferent elementalspecies can be done. Itcan be used for traceanalysis. Fast.

A large number ofinterferences are possible,such as the formation ofnon-volatile compounds,smoke formation whichwill absorb light,contamination etc.

Fluorescence Highly sensitive and thuscan detect low quantitiesof the compound in

question.

It requires expensive andsomewhat sophisticatedequipment.


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Fluorescence Preferred Detection Method

Advantages of Fluorescence:

Highly sensitive technique Up to 1,000 times moresensitive than UV / visible spectroscopy. Therefore

often used in drug or drug metabolite determinationsby HPLC with fluorimetricdetector.

Selective versatile technique Since excitation and

emission wavelengths are utilised, gives selectivity toan assay compared to UV / visible spectroscopy.


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Separation Method of Choice

Reverse phase HPLCcoupled to a Hg-specificdetector (fluorescence,photometry or otherelemental detectors).

Using an eluent ofmethanol-10 mM sodiumacetate buffer (80:20, pH6.2) containing 0.1 mM 2-mercaptobenzothiazole(MBT).

C18 column, UV detectionat 285 nm. Detection limit for Hg is

0.5 ng

Gemini 5m C18 110A HPLCMercury Cartridge 10 x 2.0mm 10/Pk8


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HPLC Schematic9


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Conclusion

By using analytical methods the mercury in thesecreams can be quantified then we can find out howtoxic/dangerous these creams really are in hopes offinding a correlation to certain health disorders in

communities in which these creams are sold.

For my analyses HPLC coupled with a fluorescencedetector would yield the best separations due to itshigh specificity, sensitivity, rapid sample analysesand sufficient detection limit for this problem.


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References

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

3. Yao-Chin Wang, Chen-Wen Whang: High-performance liquid chromatography of inorganic mercury andorganomercury with 2-mercaptobenzothiazole. Department of Chemistry, Tunghai University, Taichung 40704Taiwan. http://www.sciencedirect.com/science/article/pii/002196739380340E (accessed online, November 7,2011)

4. Skoog , D, et al. Principles of Instrumental Analysis, 6th ed.; Brooks/Cole: Belmont, CA, 2007.

5. Mercury Analysis in Environmental Samples by Cold Vapor Techniques. In: Encyclopedia of Analytical Chemistry.2006.

6. Mercury in skin-lightening creams: http://www.startribune.com/lifestyle/wellness/122598954.html

7. Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.

8. http://www.shimadzu.eu/products/chromato/hplc/modular/default.aspx

9. http://www.chemistry.adelaide.edu.au/external/soc-rel/content/hplc.htm

10. ATSDR, Toxicological Profile for Mercury, U.S. Department of Health and Human Services, Atlanta, GA, 1999.; (b)ATSDR, ToxProfiles: Mercury, U.S. Department of Health and Human Services, Atlanta, GA, 2005.

11. H. Emeteborg, N. Hadgu, D. Baxter, Journal of Analytical Atomic Spectrometry 9, (1994), 297-302.

12. High-Performance Liquid Chromatography (HPLC): www.files.chem.vt.edu/ chem-ed/sep/lc/hplc.html

13. Yong-Suk Cho, Kyo Han Ahn, "A turn-on fluorescent probe that selectively responds to inorganic mercury species"(Department of Chemistry and Center for Electro-Photo Behaviors in Advance Molecular Systems, POSTECH, San31 Hyoja-dong, Pohang 790-784, Republic of Korea) http://www.postech.ac.kr/lab/chem/mras/download/90.pdf(Accessed online October 17th, 2011)

14. Fluorescence Spectroscopy: chemistry.technion.ac.il/download.php?id=119&tbl=equations
http://www.sciencedirect.com/science/article/pii/002196739380340Ehttp://www.sciencedirect.com/science/article/pii/002196739380340Ehttp://www.shimadzu.eu/products/chromato/hplc/modular/default.aspxhttp://www.postech.ac.kr/lab/chem/mras/download/90.pdfhttp://www.postech.ac.kr/lab/chem/mras/download/90.pdfhttp://www.postech.ac.kr/lab/chem/mras/download/90.pdfhttp://www.postech.ac.kr/lab/chem/mras/download/90.pdfhttp://www.shimadzu.eu/products/chromato/hplc/modular/default.aspxhttp://www.sciencedirect.com/science/article/pii/002196739380340Ehttp://www.sciencedirect.com/science/article/pii/002196739380340E

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Analytical Presentation 1