This sounds like it is an excellent science fair project idea.
Doing a carefully controlled experiment on a basic procedure
that many scientists use for their research is definitely a
worthwhile idea. Progress in science is made one experiment at a
time, so I would encourage you to continue. The Wikipedia
article includes some background information on SDS, and
reference 6 is a link to a database for household products that
include SDS. Please note that you will have to search using all
of the alternative names for SDS, such as sodium lauryl sulfate
to find all of the products that contain this detergent.
http://en.wikipedia.org/wiki/Sodium_dodecyl_sulfate You would
need to look up some of these products and try to pick one that
does not have any other ingredients. If you can find one that
does not contain other ingredients, this would be a perfect
choice for your experiment. However, it might be best to try to
purchase the pure reagent grade SDS, even if it means filling
out the forms. Using the pure deterge