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What is the most efficient and inexpensive methods of chemical test black ink on paper...

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fdaud39366 | eNotes Newbie

Posted June 26, 2010 at 6:59 AM via web

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What is the most efficient and inexpensive methods of chemical test black ink on paper documents?

l have two paper documents written in black ink l would like to test their black ink to see if they have the same chemical characteristics, in other words from the same batch or brand.

could you please suggest a inexpensive methods as l have limited resources.

Thank you

FG

Tagged with forensic, science

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pamsuegun | Middle School Teacher | (Level 2) Adjunct Educator

Posted June 28, 2010 at 5:37 AM (Answer #1)

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Black pens from different manufacturers  are usually made using different recipes.  Black inks are a mixture of different dyes.  In my class we compare the ink from different pens using a simple paper chromatography method.  I get a round dish like a pie plate or cake pan and pour into it just enough 70% or 90% rubbing alcohol (isopropyl alcohol) to cover the bottom.  I then take a coffee filter ( the basket type) and make a dot ( about the size of this "O") on to each of the ridges of the coffee filter with each different ink.  I then place the filter in the dish with alcohol.  (It is good to use a small cup to support the middle of the filter.  If it falls and gets wet this will not work.)  Allow the filter to sit undisturbed (about 20 minutes) and you will see the filter wick up the alcohol and the ink will migrate with the alcohol.  The different dyes that make up the black ink will separate depending on the size of the dye molecules.   Some colors will travel all the way to the top of the filter and some will travel only a short distance.  The patterns of color that come from the black ink can be very beautiful. If the ink in your pens is water soluble ink you can use water instead of alcohol. 

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