Safe use of Perfluorocarbon Tracers (PFTs)
PFT's used in the Brookhaven Tracer Technology's applications to leak
detection, atmospheric tracing, and building ventilation are in the generic
class of perfluoroalkylcycloalkanes, that is, typically four (4), five (5),
or six (6) carbon member ring compounds with one (1), two (2), or three (3)
methyl groups attached to the ring.
The compounds are fully fluorinated (saturated with fluorine), contain only
carbon and fluorine, and have no unsaturated bonds. For these reasons,
these compounds are extremely stable, chemically and physically. In
the pure state, PFTs are clear, slightly viscous liquids, boiling between 45˚to
115˚C, with a density about 1.75 times that of water.
Live mouse submerged in PFT
liquid which can dissolve high
levels of 02
and C02
|
Being chemically extremely stable
also makes them biologically very inert. PFTs can be inhaled and
ingested with no concern. For example, in the article "The
(liquid) Breath of Life" (Science, Vol. 245, pp. 1043-1045, 8
Sept. 1989), a perfluorocarbon fluid in the lungs of a premature
infant can facilitate normal breathing in the immature lung
membranes. The article also mentions the use of perfluorocarbons
as artificial blood substitutes (p. 1045) as does the article
"Different Paths to a Human Blood Substitute" (NY Times, p. D5,
8 July 1992). Since the PFTs are safe for human exposure at high
concentration, there is certainly no concern for their levels in
tracer technology applications.
PFTs also have no environmental consequence. Their fluorine
atoms do not chain react with ozone; therefore PFTs do not
affect the ozone layer as do conventional chlorofluorocarbon
compounds (CFCs). Also, CFCs are less stable chemically and
therefore more reactive biologically than PFTs. The sum total
ambient air background concentration of all CFCs plus carbon
tetrachloride (130 ppt) and methyl chloroform (135 ppt), the
latter two of which are even more reactive, exceeds 100 ppt
(parts-per-trillion); this concentration is in every breath we
take. |
On the other hand, the ambient background of all PFTs is about 0.03 ppt,
about 30,000 times smaller. Even in building ventilation studies, the
indoor air concentration of PFTs is always 10 times smaller than the total
CFC levels that are inhaled continually; in most leak detection and
atmospheric tracing applications, the outdoor concentration is usually 1000
times smaller than that of CFCs. Thus, there can be no consequence of
using the PFTs in any of these applications.
Last Modified: July 29, 2008
Please forward all questions about this site to:
Linda Satalino
|
