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### Topic: Detecting Gasoline  (Read 26009 times)

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#### Joeay

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##### Detecting Gasoline
« on: May 16, 2006, 05:20:39 PM »
Hello, I'm not sure if this is the section for this question, however I'll try anyhow.

I was wondering how one would detect if the presence of gasoline would be located in a soil sample? I would also need to know the level of concentration, or atleast approximately. I have been reading a little about gas chromatographs but am not sure if this would be the answer, or the only answer. I am also hoping there is a cheaper alternative. Thanks a lot!

#### rctrackstar2007

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##### Re: Detecting Gasoline
« Reply #1 on: May 16, 2006, 06:56:17 PM »
what do you need to detect it for, one method would be to wear gloves and non-flammable things and light a small flame near it to see if it ignites, tho i would avoid this

The world is like an atom. The not-quite-as-intelligent people are the nucleus all packed together sharing a common...everything. We, we are the electrons. Granted we're not as smart as these engineers and what-not so we're most likely in the first orbital, but we're the electrons of this giant atom. We all have differing intelligences and ideas and we are separated from the nucleus which makes us better because no one really cares about how a nucleus acts. It's the electrons that make chemistry, except for nuclear chem, of course, which I am a big fan of.

-Your's truly, 2006;
written to describe the HS chem student apart from the average being

#### syko sykes

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##### Re: Detecting Gasoline
« Reply #2 on: May 16, 2006, 07:02:54 PM »
what do you need to detect it for, one method would be to wear gloves and non-flammable things and light a small flame near it to see if it ignites, tho i would avoid this
lol, fire isn't the answer to everything... and even if you did get soil to ignite that wouldn't insure that gasoline was the cause nor would it tell the concentration

hell, smelling the ground would be a better idea... if it smells like gas then it probably contains some gasoline, the stronger the smell the higher the concentration (and this would definitely be the cheapest approach)

on a more serious note, couldn't you do a mass spec. or something like that

#### rctrackstar2007

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##### Re: Detecting Gasoline
« Reply #3 on: May 16, 2006, 07:17:33 PM »
i was just trying to keep the cheap approach to it

if it does ignite, it wouldn't be spontaneous but you could move around the flame to catch everywhere and when you're done, there is no concentration. unless you need the numbers for something then just ignore what i said

The world is like an atom. The not-quite-as-intelligent people are the nucleus all packed together sharing a common...everything. We, we are the electrons. Granted we're not as smart as these engineers and what-not so we're most likely in the first orbital, but we're the electrons of this giant atom. We all have differing intelligences and ideas and we are separated from the nucleus which makes us better because no one really cares about how a nucleus acts. It's the electrons that make chemistry, except for nuclear chem, of course, which I am a big fan of.

-Your's truly, 2006;
written to describe the HS chem student apart from the average being

#### Joeay

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##### Re: Detecting Gasoline
« Reply #4 on: May 16, 2006, 09:29:42 PM »
on a more serious note, couldn't you do a mass spec. or something like that

Could you perhaps expand on that idea? Sorry, I'm no chemist.

I am trying to find a way to do this on my own, because going through a lab cost 1500$per test. All I need is an approximate of the amount of gas so that I don't have to trial and error and take multiple tests, doesent have to be exact although the more precise the better. I am willing to do whatever it takes to learn what I need. Like I said, I've been searching on the net for some time, but have not had luck. Any help is really appreciated. #### mike • Retired Staff • Sr. Member • Posts: 1246 • Mole Snacks: +121/-35 • Gender: ##### Re: Detecting Gasoline « Reply #5 on: May 16, 2006, 09:38:02 PM » There is no science without fancy, and no art without facts. #### syko sykes • Full Member • Posts: 128 • Mole Snacks: +12/-10 • Gender: ##### Re: Detecting Gasoline « Reply #6 on: May 16, 2006, 10:22:59 PM » on a more serious note, couldn't you do a mass spec. or something like that Could you perhaps expand on that idea? Sorry, I'm no chemist. I am trying to find a way to do this on my own, because going through a lab cost 1500$ per test. All I need is an approximate of the amount of gas so that I don't have to trial and error and take multiple tests, doesent have to be exact although the more precise the better.

I am willing to do whatever it takes to learn what I need. Like I said, I've been searching on the net for some time, but have not had luck. Any help is really appreciated.
i wish i could but i have to be honest and say i really don't know much about that particular area either... i am pretty sure however that there is no way to do this without doing a lab test

here's about the extent of my knowledge:
mass spec. means mass spectrometry which dictionary.com defines as:
"an instrumental method for identifying the chemical constitution of a substance by means of the separation of gaseous ions according to their differing mass and charge called also mass spectroscopy"
http://dictionary.reference.com/search?q=Mass%20Spectrometry

most labs, at least the good ones, have machines that do this but i don't know if it would work on soil since it isn't a gas... perhaps a mod could give us some more information on this or lead you in a different direction

also, mike's website appears to give a very detailed description of how to solve your problem

#### Joeay

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##### Re: Detecting Gasoline
« Reply #7 on: May 16, 2006, 10:34:35 PM »
Mikes website was not exacly what i needed however it did point me in the good direction such as the right terminology to search.

it seems i must use a TPH 1,2 test method. After searching this I found an ebook named Analytical Methods For Petroleum Hydrocarbons. As I stated before, I'm no chemist. But I'm hoping this book could teach me a thing or two. If this is totally the opposit from what i need let me know. I'd still like help from the experts

#### mike

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##### Re: Detecting Gasoline
« Reply #8 on: May 16, 2006, 10:44:02 PM »
Quote
Mikes website was not exacly what i needed however it did point me in the good direction such as the right terminology to search.

That was the idea
There is no science without fancy, and no art without facts.

#### Borek

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##### Re: Detecting Gasoline
« Reply #9 on: May 17, 2006, 03:20:04 AM »
I don't know if it would work on soil since it isn't a gas...

Doesn't matter - you can heat up the sample and volatile substances will become gaseous...

that's the way you do it.

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#### mike

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##### Re: Detecting Gasoline
« Reply #10 on: May 17, 2006, 03:21:30 AM »
There is no science without fancy, and no art without facts.

#### Borek

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##### Re: Detecting Gasoline
« Reply #11 on: May 17, 2006, 03:40:36 AM »
+1
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#### Joeay

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##### Re: Detecting Gasoline
« Reply #12 on: May 17, 2006, 06:14:51 AM »
I don't know if it would work on soil since it isn't a gas...

Doesn't matter - you can heat up the sample and volatile substances will become gaseous...

I suppose that would work if there is a small sample. I also read that this is how the gas chromatograph (i believe thats the word) works this way, however gives a detailed output. Is there an instrument that would detect and calculate the amount of the fumes from the gas?

#### Borek

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##### Re: Detecting Gasoline
« Reply #13 on: May 17, 2006, 06:59:09 AM »
Problem is - most analytical methods give you information about individual compounds. Gasoline is a mixture of different hydrocarbons and it is not clear to me how to translate individual compounds into "gasoline amount". Additionally, these different hydrocarbons have different volatility, so they will evaporate from the soil with different speeds - so their composition in soil will change with time, making problem even more complex.

I suppose that there are some norms and methods defined by gov agencies that allow for such measurements, but the result is - at least partially - a matter of convention (just like soil pH is). As long as you follow the convention you may compare results of measurements done in the different places, but measurement doesn give exact answer to the "gasoline amount" question, as the question is not exact. Perhaps if you will ask for "total hydrocarbons" it will be much easier - it will be enough to add all HC concentrations to get some number of more or less well defined meaning.

I suppose that would work if there is a small sample.

You always work this way - you get small sample to analyze.

Is there an instrument that would detect and calculate the amount of the fumes from the gas?

What do you mean by "amount of the fumes from the gas"? But perhaps I have already answered your question above?
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#### xiankai

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##### Re: Detecting Gasoline
« Reply #14 on: May 17, 2006, 09:54:04 AM »
how about fractional distillation? u can check the boiling temperature of the liquid mixture at different intervals after cooling down the soil sample to produce a liquid which composes of those HCs
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