Wal-Mart Corporation sees a marketing opportunity in Lakewood Colorado one of the Western suburbs (of Denver)
at the corner of Colfax and Wadsworth
They find a series of lots for sale.
it's 30 acres , approximately 1000 feet 1000 feet
big enough for Wal-Mart
On the corner of Colfax there is a bank and small restaurant
they plan on leaving the bank and the restaurant
next to it, along Colfax (avenue), is a small shopette
that holds, among other things a paint recycling store
along Wadsworth (avenue) on the other side is an auto detail place
that specializes in painting cars
there is a small stream that
goes across the back of the property
As part of the sale , the title company looks
at the past use of this commercial property and
finds that the shopette was built in 1963
before that and for many years the property was a Chevy dealership
and before that, all through the 1930s and 1940s
the property was a junkyard
they furthermore find that at the corner there was
a gas station complete with underground gas tanks
that was torn down in 1963
there is no record as to whether the storage tanks were removed or not
presently there is a painting establishment
in two places both along Wadsworth with the car detailing place
and the shopette has a paint recycling place
both of which are suspicious
It is very clear that an environmental assessment
needs to be done on the property
before it is sold
the reason for the environmental assessment is really,
there's a lot of reasons, but one of them is to protect Wal-Mart
If there is environmental problems on the property
these need to be recognized before
Wal-Mart goes in so that Wal-Mart doesn't get blamed for it
and furthermore
if there are problems and they are bad they need to be cleaned up now before the building is built
when a real estate transaction is done on commercial property
there is usually an environmental assessment
the environmental assessment is performed by
an environmental consulting company
the environmental consulting company consists of environmental engineers
these are people that are specialized in soil types
and soil percolation and distribution of hazardous-waste
through layers of soil and maybe
it has to do with building
it has to do with the law
I don't really know very much about it
the environmental consulting company has to hire a lab.
by regulation the lab has to be independent
which is where we come in
the purchase price of the 30 acres is $3.5 million
of that 3.5 million , $400,000 of it is earmarked
for the environmental assessment
so the environmental business is a pretty big business
and there are jobs in this business
the environmental consulting companies goes to the site
and looking at the property
looking at the geology and geography they decide
what tests they need to have run in order to determine if there is hazardous waste
one of the tests that they will order is the EPA 8270
the 8270 is GC mass spec analysis of the organic components
in soil or water
as often happens, it is defined by the conditions of the test
the 8270 is an analysis for organic materials that are extractable by methylene chloride
materials that are extractable by methylene chloride include everything that's organic
I think everything organic
so it doesn't include for example chromate, lead or cyanide
but it includes anything that is organic
anything is petroleum-based
any organic solvents anything that has to do with paint
anything that has to do with the manufacture of plastic
or the disposal of plastic
old tires or grease or asphalt or anything like that
will be extractable by methylene chloride and will be identified by
the 8270 gas chromatography / mass spectrometry analysis the GCMS 8270
The 8270 starts out with a liquid liquid extraction
And that is where we want to start right now
we want to take a more careful look at the liquid liquid extraction
liquid liquid extraction is done in methylene chloride.
Methylene chloride is dichloromethane. It is symmetrical. This bond rotates so there is no dipole
no up/down
no top or bottom.. no nothing.. it's round , figuratively speaking
it is symmetrical it doesn't have a dipole. There is nothing that looks like a magnet..
water is, of course, a triangular substance. there is a positive/ negative.
water is hydrophilic.. methylene chloride is hydrophobic...
they say "like dissolves like"
we need another player. let's use naphthalene.
naphthalene is two benzene rings put together,
a set fairly common pollutant , is moth balls in common language.
it has a boiling point of maybe 130 or something like that
so its solid at room temperature
it has a limited solubility in water,
so it's not completely insoluble in water
it's important to understand that it has limited solubility
so the equilibrium takes place where
the methylene chloride meets the water,
so it doesn't happen in the water and
it doesn't happen in the methylene chloride
it happens where the methylene chloride meets the water
a molecule of naphthalene comes to interface between water and methylene chloride
what's it going to do?
is naphthalene going to stay in the water or is it going to go into the methylene chloride
the probability is that it will go into the methylene chloride
is the a probability, not a statement of fact
It will tend to want to go into the methylene chloride
so what is the purpose of the separatory funnel
separatory funnel
your instinct would be to say that you shake
the separatory funnel and the action of shaking the separatory funnel
forces the naphthalene into the methylene chloride but that's not the case at all
shaking the separatory funnel only increases
the surface area between the water and methylene chloride
and allows the equilibrium
to happen sooner
the standard procedure is to put water , liter of water,(the sample) into a rather
large separatory funnel Its about this big
add hundred milliliters of methylene chloride to it
shake it up
let's say 85% of the naphthalene will go into the methylene chloride
let it sit
if the water is clean it will quite quickly separate
drain the methylene chloride into a beaker (out the valve at the bottom)
add hundred milliliters more methylene chloride
shake it again
drain the methylene chloride
into the same beaker and do it a third time
the first time, about 85% of the naphthalene will go into the
methylene chloride
the second time 85% of the remaining naphthalene
will go into the methylene chloride
so after two extractions there's not very much naphthalene left
do it a third time and you will end up with
98% of the naphthalene in the methylene chloride
Your intuition would say that
shaking the separatory funnel
drives naphthalene into the methylene chloride
but that's not the case at all
shaking the separatory funnel
only increases the surface area and
allows the natural equilibrium to occur faster
the methylene chloride does not go out and grab the naphthalene
the methylene chloride simply accepts it more readily
than water
and that's all there is to it
the 8270 is a good subject for study
The 8270. the EPA 8270, is GC mass spec analysis is one of
the oldest established mass spec analyses there is
it has been around as long as quadrupole mass spec
which is probably on the order of 25 years ,maybe 30 years
it has been around a long time
I think of the 8270 as the grandfather
of all mass spec analysis
everything came out of the 8270
this is my perception but whatever
the 8270 is a good subject for study because the
8270 is a very typical analysis
involves a liquid liquid extraction... ....very common
involves a blow down procedure.... very common
it involves calibration using internal standards
which is very common
there is a concentration step ...
it is a very ordinary analysis.
I think that this is a good subject
the 8270 is a good time to stop and really look closely at something