[Aqualist] LOI advice - glazed at 950 C?

[Matthew Lybolt]

Hello list members, 

 

I'm planning to use loss-on-ignition (LOI) on reef sediments. I'm
testing whether changes in character and quantity of terriginous
sediments delivered to reefs are correlated with changes in the reef
community structure. The bulk sample, and the non-carbonate residue from
the furnace, will go through laser particle size analyses. I've skimmed
the literature, read the AquaList thread on LOI, and the detailed
examination of LOI methodology by Heiri et al 2001.  But several
questions remain (which are probably so obvious nobody bothered to write
them down): 

 

Does it matter whether I use glazed or unglazed porcelain crucibles for
my treatments? (1-2 g dry weight, 4 h @ 550 C, 2 h @ 950 C)

 

Do the lids remain on or off during the treatment? 

 

What are the disadvantages to weighting the crucibles while warmer than
100 C, to avoid the need for desiccators?  

 

What material is suitable for a crucible tray, to avoid handling (and
spilling) individual crucibles inside the furnace?  

 

I'll distribute your advice to 3 other PhD students who are interested
in LOI for reef sediments.  

 

Thank you!  

Matt

 

Matt Lybolt - PhD Student - Marine Palaeoecology Lab

Centre for Marine Studies and ARC Centre of Excellence for Coral Reef
Studies

University of Queensland, Brisbane, QLD 4072, Australia

m.lybolt at uq.edu.au

(w) +61 (0)7 3365 9001 - (f) +61 (0)7 3365 4755 - (m) +61 (0)431 923 552

http://www.cms.uq.edu.au/

http://www.coralcoe.org.au/ <http://www.coralcoe.org.au/>