Conservation DistList Archives [Date] [Subject] [Author] [SEARCH]

Subject: "Lignin-free" boxes

"Lignin-free" boxes

From: Walter Henry <whenry<-a>
Date: Friday, November 18, 1988
as for phloroglucinol: its a bit sticky. the test is easily misread,
especially on coloured materials like board.  more relevantly, the
solution is incredibly unstable, so if it is more than about 12
microseconds old, you cant quite trust it.  it is also semi-quantitative
so it will respond differently to different lignin concentrations (which
probably isnt relevant here).  nevertheless, if you have used the
solution on known blanks (filter paper, newsprint, and, best, some
similar coloured board known to contain lignin) and are getting
unambiguous positives, then by all means, the burden of proof would seem
to be on them.  however, what they told you 'it's easy to get false
readings with phloroglucinol' is quite correct. Ive started buying phl.
from talas: they sell it in two parts, the phloroglucinol solution
itself and the acid separately, so that you can mix it up at test-time
and be sure of a reasonably active solution.  so far it seems to be
working well, though next time I will probably just break down and buy
the native chemicals and mix it up myself (go halveseys with some other
lab, maybe).

    **** Moderator's comments: anyone interested?

                   Conservation DistList Instance 2:8
                 Distributed: Sunday, December 11, 1988
                        Message Id: cdl-2-8-004
Received on Friday, 18 November, 1988

[Search all CoOL documents]