Subject: why do we use pencil for paper chromatography

rather than using pen we use pencil to mark on chromatography paperwhy do we 
do like so?

Response:

Re: why do we use pencil for paper chromatography

Greetings Amal,

Thanks for submitting your question about chromatography to the MadSci Network. 
I am pleased to let you know that questions related to yours have been answered 
on our site. You can also use our search engine to locate answers containing the 
word(s) chromatography:
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A pencil mark consists of shards of lead or graphite that are physically abraded
from the pencil tip and are held onto the surface of the paper by mechanical
forces. Ink is a solution that adsorbs onto the surface of the paper. Because it
is a solution, some of the components of the ink may be soluble in the solvent
you are using in your chromatography, in which case the ink mark will spread
as the solvent front advances. The easiest way to find the answer to this question
is to try it with various inks from various pens as well as marks from several pencils.

If, after reviewing the previous answers, you still have a question, feel free to 
submit a new question, but please be sure to tell us that you have already 
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Cheers!

Steve Mack, Moderator MadSci Network

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rather than using pen we use pencil to mark on chromatography paperwhy do we 
do like so?


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