**Great Suggestions, Observations, and Modifications for Activity
3.3-Chromatography**

The great staff here at OMSI working with me on JASON trainings has put
an enormous amount of work into how best to present the activities. It
has been a work-in-progress and I didn\'t share this sooner as I didn\'t
want to rush to \"publication\" (you remember cold fusion). Anyway,
after many, many trials, we concluded that the JASON method of preparing
the filter paper worked very well but\.... it worked just as well
soaking for 12hrs or 6 hrs or 3 hrs or even just dunking them in and
getting them wet and letting them dry. Next, we eliminated the
preparation altogether and still got very good results. That is, we
didn\'t soak the paper in anything before adding the spinach or carrot
and putting it in the alcohol. As for the spinach and carrot prep, we
found that rolling the edge a coin or edge of a spoon over a fresh
spinach leaf directly onto the filter paper transfered crushed leaf  and
worked very well (repeated rolling transfers even more material). And we
just used well-shaken Odwalla carrot juice for the carrot (overall the
carrot signature is not as good as the spinach). We experimented with
many different organic substances and if you like, please contact me and
I\'ll put you in touch with the educators who did the work and they can
outline all that was done. Bottom line is that while the JASON procedure
works, it is not ultimately necessary to get good results. I hope this
helps and recommend trying these suggestions yourself before doing it
with teachers.

Blair Baldwin

Professional Development and Distance Education Manager

JASON Project Coordinator

Oregon Museum of Science and Industry (OMSI)

In our training, we explain that different pigments combine to from
various colors; in nature, of course, these pigments are only made by
living things. The particular set of pigments that one species can form
is determined by its DNA, and is therefore the biosignature of that
species, whether it's spinach or carrots, etc.

We cut plain white card stock paper into 1cm x 8cm strips and do not
treat it. We have three different brands of black felt-tip pens. We tell
each participant to choose one pen, write its "name" somewhere so as to
be sure to remember which one was chosen. Each person gets one paper
strip, writes his name on the back in PENCIL, then draws a line across
the paper strip about 1cm from one end with the black marker he has
chosen. Only three pens are used, passed along throughout the
participants, so some people will have used the same pen.

We place the paper strips into a glass container, (the end with the
stripe down), pour in just enough (91%) isopropyl alcohol to cover .5cm
of the paper's end. We explain that the paper (card stock) will act as a
wick to pull the solvent (alcohol) upward. As the solvent passes through
the ink stripe, it will dissolve the ink. The particles of ink pigment
will then "run" with the alcohol as it is drawn up the paper "wick"; the
densest particles/molecules will be dropped first, less dense molecules
carried farther, and the least dense molecules carried farthest as the
alcohol creeps upward. After only about half an hour, we see results;
the longer the strips are left in the alcohol, the better. We usually
examine the paper strips after 1 hour, compare which participants chose
the same black pen, based on the chromatogram and each participant's own
record. Then we compare our "model" of chromatography as an indicator of
biosignatures to looking for such chemical signatures from once-living
things on Mars. This also works well with colored felt tip pens, but the
black is so much fun, because different manufacturers use different
combinations of other colors to make black. One chromatogram will be
gray particles, followed by blue; another will be black particles,
followed by red, yellow, blue; another will be totally different. Each
type of ink will form the same array in a chromatogram every time, as
its signature.

Mary Jane Shands

JASON Coordinator

University of Texas, Brownville