This news item was created by students
Lesley Davis, Jr., Scott Dudley, Kelly Mandl, Diana
Rau, Jeff Sindelar, and TJ Soyoye
as part of
their Chemistry 212 Collaborative Group Activities in WS00 under the
guidance of Prof. Rainer Glaser.
"Chemistry is in the News"
To Accompany Wade
Organic Chemistry 4/e.
Chapter 24. Amino
For each of the following questions, please refer to the following
ARE LEAVING FEWER STREAKS
by Angela Pirisi (The Gazette [Montreal], 1998)
Beauty is in the eye of the beholder and a "beautiful tan" is
something sought after by millions upon millions of people yearly in
the United States. We have all heard the catch phrases since we
were old enough to slip on our first swimsuit, from the
aforementioned 'beautiful tan' to the ever so ironic 'healthy tan'.
The society we live in places great emphasis on appearance, and the
ritual of tanning is a major factor in that appearance.
Unfortunately, the tan that we have all grown to love and has proved
to have some long-term shortcomings, with a greatly increased
likelihood of skin
cancer being at the top of the
A silly as it sounds, people still choose the short-term appearance
and disregard the proven long-term adverse effects. Old habits die
hard, and sadly the rates of deaths from skin cancer
Fortunately, another catch phrase is beginning to be heard, the
so-called 'fake tan'. The potential for profit is fueling the
development of chemicals that provide a tan equivalent to that of
the best beach bum's tan-- one with none of the harmful risks.
Males and females alike are concerned about how pale their skin is;
however, they still have to worry about the growing threat of skin cancer.
What could be done to give skin the bronzed look in the middle of the
winter without someone worrying about the harmful UV rays absorbed
For years many have relied on the help of 'fake tans' straight from
the bottle. Often, however, many people ignore this route because
these self-tanners are streaky at best and have a foul odor to
The bad smell is associated with sugar-like chemicals such as dihydroxyacetone (DHA). Recently,
thought, there have been
wonderful advances in the field of self-tanners, giving a more
natural look with much less of a foul smell.
The DHA in these self-tanners form colored complexes with the amino
acids in the skin; these kinds of tan vary from person to person
because of other factors like skin thickness,
skin pH, melanin levels, and the
amount of melanoids produced within the skin. Strange
discolorations and inevitable streaking have been the direct result
of these other factors. Not every individual's skin is the same,
and what may work for one person and produce great results may
not work at all for someone else. The different acidity levels of most
everyone's skin produce different color results for everyone.
These so-called 'fake tans' are a wonderful alternative to the real
thing; they even help those persons with skin diseases or
problems that prevent them from being exposed to large amounts of UV
rays. They also come in a variety of types: some self-tanners [like
those from Lanc™me and Christian Dior] contain
alpha-hydroxy acetone (AHA), and some
[like those from Clarin] contain sunsreen. The
included article details self-tanners and DHA and some of these
products and provides information that can educate
'tanners' and 'fake-tanners' alike.
Pertinent Text References
- amino acids, peptides, proteins, and
acidity: pg 1119
- reactions of amino acids: pg 1133
- ketones and aldehydes: pg 785
Question 1: Compare the structures and uses of AHA and
DHA. Include IUPAC names for both.
Question 2: How do melanoidins
and melanins differ?
What is the chemical reaction that is responsible for the unpleasant odor
associated with tans?
According to the article, the effects of a fake tan are due to a few
factors. Describe those factors and explain how skin pH
alters the effect.
Question 5: There have been many improvements made to
products, as described in the article. What are some of these
improvemnets and what
other improvements may be made to self-tanners to meet the consumers needs