CHEMISTRY ENHANCEMENT COURSE

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CHEMISTRY ENHANCEMENT COURSE Dr David J McGarvey
INVESTIGATING COMMERCIAL SUNSCREENS
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OVERVIEW

• What is this practical about?
• Review of practical techniques.
• IT Plot several graphs on the one plot.
• IT Enter data into Excel, plot a straight line
  graph and obtain its slope and intercept.
• Ciba Sunscreen Simulator

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How do Suncreams Work?
ABSORBED
ULTRAVIOLET
VISIBLE
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HOW DO SUNSCREENS WORK?
UVB SUNBURN, SKIN CANCER, AGEING UVA SKIN
CANCER, AGEING, TANNING
UVB SPF UVA
?????
http//www.loreal.com/
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How do Sunscreens Work?
cis
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How do Sunscreens Work?
cis
trans
photoisomerisation
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How do Suncreams Work?
2-EHCDP
MBC
Octocrylene
Cinnamates
Mexoryl SX

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How do Sunscreens Work?
Z-E
E-E
http//www.loreal.com/
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How do Sunscreens Work?
photoisomerisation
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GAS-CHROMATOGRAPHY MASS SPECTROMETRY
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OBJECTIVES

• Obtain the UV absorption spectra and ?max values
  of the three sunscreens.
• Use the Beer-Lambert law to determine the molar
  absorption coefficient (?) of one of the
  sunscreens (you will be told which).
• Compare your ?max values and molar absorption
  coefficient with the values published by DSM.
• Investigate the effects of exposure of the
  sunscreen solutions to UV light using UV-VIS
  spectrophotometry and GC-MS data.
• Use the Ciba on-line sunscreen simulator to
  formulate sunscreens with prescribed SPF and UVA
  protection factors.

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REVIEW OF PRACTICAL TECHNIQUES

• Taking samples
• Use and care of quartz cuvettes
• Use and care of autopipettes
• Use of spectrophotometers
• Waste disposal
• PLEASE TIDY UP AT THE END OF THE DAY

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https//www.cibasc.com/pccibasunscreensimulator/
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