Aromatic hydrocarbons, so named for their characteristic strong, sweet odor,
are found naturally in volcanoes and wood fires. They are produced
commercially with many industrial uses, most notably to us as a solvent,
also as a additive in jet fuel, perfumes, paint, nail lacquer, and bug
repellents.

Xylene occurs naturally in crude oil but is supplemented by additional
amounts made in the refining process. Commercial xylene, generally referred
to as xylene (mixed isomer), or technical grade xylene, is a mixture of
widely varying proportions of four isomers - xylene, ortho-xylene,
meta-xylene and para-xylene, together with ethylbenzene 6-20% and smaller
amounts of toluene, trimethylbenzene, phenol, thiophene and pyridine. As a
solvent, xylene evaporates more rapidly without these trace elements which
are removed (evaporated) by re-distillation in the lab. The lack of these
trace elements can also effect the automated coverslipping process. I have
recycled xylene for many years without comprimising the results of any other
laboratory procedure. 

Xylene can last in the air as we know for 48-72 hours, but can be broken
down rapidly by sunlight. Which is one excellent reason to have a Histology
with many windows and sufficient ventillation!

Eric C. Kellar
Histology/Immunohistochemistry
University of Pittsburgh Medical Center


-----Original Message-----
From: Weems, Joyce
To: 'Histonet'
Sent: 4/19/99 10:20 AM
Subject: Recycled Xylene

Would you all give me your opinion of recycled xylene. Ours has come
upon attack, and I would like to know what the rest of the world thinks!
Thank you, J:>)
JOYCE WEEMS
PATHOLOGY LAB MANAGER
SAINT JOSEPH'S HOSPITAL OF ATLANTA