Subject: "Lignin-free" boxes
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