Invisible ink

The following appeared in sci.chem and is reposted her without the
knowledge or consent of the authors

    From: klier [at] iscsvax__uni__edu
    Newsgroups: sci.chem
    Subject: Invisible ink
    Date: 22 Sep 91
    Organization: University of Northern Iowa

    In article <1991Sep12.121051.9048 [at] sobeco__com>, dchouina [at] sobeco__com
        (d.chouinard) writes:
    > In <1991Sep12.075532.8549 [at] nntp__hut__fi> rluoma [at] hila__hut__fi
    >    (Rauno Luoma) writes:
    >
    >>I need invisible ink that is visible in UV-light for ex.
    >>Does anyone one some that are easy to make and use on paper
    >>and also stable enough to stay invisible for many years
    >
    >
    >>Rauno Luoma                                phone +358-0-4512778
    >>M.Sc                                       internet Rauno.Luoma [at] hut__fi
    >>Helsinki University of Technology
    >>Laboratory of Metallurgy                   home  +358-0-822426
    >
    > In my old and wild days as a youngster, we used "Murine" (liquid
    >for the treatment of red eyes.)  It used to fluoresce a beautiful
    >purple under the light of popular "black lights."  Yes, "Murine" is
    >a stupid name; but the product was marketed under it.  I guess most
    >eye liquids will probably contain the same stuff.

    Most flower pigments are flavonoids, and even white flowers have
    flavonoids. You can easily extract flavonoid glycosides by grinding
    flowers with 70% EtOH, then evaporating the residue until it's as
    thick as you wish.

    If you wish to make the aglycones, hydrolyze the crude extract with
    dilute HCl and heat.  This is useful if you require a polar solvent
    for your ink.

    Flavonoids are stable on paper for >400 yrs, if we can judge by
    herbarium specimens from the 1500's.

    Kay Klier
    Biology Dept, UNI

                                  ***
                  Conservation DistList Instance 5:22
                  Distributed: Sunday, October 6, 1991
                        Message Id: cdl-5-22-004
                                  ***