Micro Gas Chromatograph System Training


Uploaded by techEIU on 20.10.2011

Transcript:
[no dialogue]
>> male speaker: A Micro GC has
two modules in it or two channels in it.
One channel has a molecular sieve, the other has Pora Plot
Q, the one that you have.
Each one of those channels has an injector.
Each one of those has it's own column, obviously the two
columns I just named, and each one has it's own TCD detector.
So, what we do is we take the sample and it splits and it runs
in both of them in parallel and then we take that information
and we just do an external standard and say that, "Okay,
based on what our external standard is there's how much of
this product is in this unknown gas that we're going to run."
The way that it will come out, the elution order, and I suppose
you have argon carrier and helium.
Yeah, right.
The reason that we do that is because the thermal conductivity
for helium and hydrogen are identical, relatively
close to being identical.
So, you're going to get the same response.
If you run helium as a reference gas through a TCD,
you won't see anything.
Actually, you will for hydrogen and it's kind
of an interesting compound.
It'll go positive for a little bit and
then it will go negative.
This causes a problem because you never know where the start
of the peak is and everybody's a little hazy
on where that crossover point is.
I like to think that if you're doing anything lower than 2%,
you can probably do it on helium.
If you're doing anything above 10%, you could probably do it on
helium by inverting the signal.
But there's that area, around maybe 20%, so there's that area
in between that's just an upset baseline.
So, we run argon because there's great thermal conductivity
between argon and helium, and we invert the signal and we get a
really nice little sharp peak.
What that does for you though, is it reduces the sensitivity
for some of the other compounds.
Not that it's going to effect you guys because the thermal
conductivity is relatively close on argon and CO.
So, instead of seeing like we normally can of helium, we can
see about 10 parts per million of CO.
With the argon carrier, we'd be lucky to get about 200 parts.
Again, well below what you want to see.
So, the elution order on a mole seive is going to be
hydrogen, then we're going to see oxygen and nitrogen.
And then we'll see either CO or methane they'll be kind of close
together depending on how well that column is separating them
and what temperature we run.
You can heat and drive CO in front of the methane but I like
to leave it cool enough so that we can see
the methane before we see the CO.
CO is kind of an odd little peak in that it has a little bit of a
tail to it, and if it's in front of methane, sometimes we can't
get a good separation.
Now, after that we're going to backflush it.
So, the main thing that affects a mole seive adversely is going
to be water, doesn't like water, gas generally has water.
It also doesn't like the CO2 and it has two
different affects on the mole sieve.
One is on a mole sieve, the elution will start, all of the
peaks will start shifting forward and that means it's wet.
If you start losing sensitivity on everything, that's CO2.
That's harder to get rid of.
The main thing we want to do is make sure we get CO2 off of that
and keep it off of that, which shouldn't be hard to do at 10%.
The other column is specifically, because it's got a
little pre-column on there and we hold up the CO2 just briefly
and then we backflush it to vent.
On the poor plaque cube, we've got a composite peak that'll
be all this stuff, except for the methane which
we'll be separating in a little bit.
Then we'll get CO2, ethane, ethylene, ethane.
If you separate those two and then you'll get propane,
propylene, propane.
In between here you might get a little water peak.
So, these are C3s, these are C2s, this is CO2,
this is C1 and CH4.
Okay.
So, that's the basic principle.
You're doing this--
>> male speaker: Can you show us one
more time because none of us are chemists.
>> male speaker: Sure.
Alright.
That's okay because you don't have to be a chemist, you have
to know what the elution order is and i'm
sorry let me turn that off.
>> male voice-over: This is super important
for us to understand.
>> male speaker: Yeah, I mean it will be named
and it'll be done by retention time but this should
always hold true because the retention time is going to
be set by whatever we set the pressure to be on the column.
So, we're going to see helium, we're going to see hydrogen,
oxygen, nitrogen, and then methane and CO.
On this other peak, on this other one, we're going to see an
air peak, what we're going to call an air peak or a composite
peak, that we won't analyze.
We probably won't analyze methane, we'll probably do it on
the other one, and then we'll start at CO2, C2s, C3s.
If there's water, it'll be right in between the two of them.
Water is a distinctive peak.
>> male voice-over: This is for the GC 2?
>> male speaker: This is the mole sieve.
>> male voice-over: Mole sieve?
>> male speaker: Yeah.
>> male voice-over: This is for the molecular sieve?
>> male speaker: Mole sieve 5 8.
And this is a phorus polymers cube.
So, that's the basic principle of it.
Another thing you need to remember about the micro gc:
don't put water on it, don't put any liquids in it, don't put any
particular matter in it.
There are actually two filters on this system.
One of them you can see that it's on the outside when Burt
set it up, which is right here.
It's a little 5 micron frit.
It's exchangeable.
So, if you see that you're not getting the sample in, you might
want to check that frit and see if there's anything on it.
The other is, there's another exact match for that
frit, the 5 micron frit, inside this fitting.
Don't ever get anything in there because you
have got to replace this fitting.
That's why we have the external filter on it.
So, that's it in a nutshell.
>> male speaker: It looks like maybe
we're going to do more details after the video session.
>> male speaker: Okay.
>> male speaker: The video sesssion,
I would suggest, maybe walk us through
the process, the method.
>> male speaker: Method process?
Got it.
[unclear dialogue]
Okay.
That's what we'll do.
We'll go in there right now.
>> male voiceover: Okay, so to build a
method, the first thing we need to do is
running on experience, which is what I'm going to do I'm going
to guess at what these are.
The things we need to set up would be the pressure, the
temperature, and the length of the run.
So, the first thing is I'm going to take this little cool down
method that we have and save it as something
completely different.
Let me see if you've got one out here first.
You have a couple.
Is this an air sample method?
[unclear dialogue]
Burt, Burt did that one I think.
>> male speaker: Pardon?
>> male speaker: Well, it's always just as
easy to, I don't think you'll ever have to
do a new one but if you did, you can.
It's going to pop up with the same things that are in the
cool down.
So let's go from the very beginning.
Let's back all the way up.
We don't care about these.
So, we start from scratch.
First thing is we click on this EZChrom.
And it always opens up with the last thing that you did.
I don't like this little screen to pop up so I'll turn it off
and you won't see it again.
This is a wizard for creating a sequence, a wizard for creating
a method, doing a single run or running a sequence.
Everything that, there's 4 or 5 ways to get
to everything in this software.
One is through the file menu, where you an open up a method.
You can open it up in different arears, you can save methods if
you go through here and save it there.
Or you can do a pull down on this icon and save it.
I have a tendency to mix up the two.
So, I'll just do it the way that I normally would do.
You can understand that there's more than one way to get there.
The first thing we'll do is to tell this instrument what
temperature it needs to run at and what pressure it needs to
run at becasue we need to start getting the temperature up to a
level that we can work with.
So, the first thing I'm going to do is go and do a new method.
You shouldn't have to do this very often.
And in this new method, I'm going to tell it that the
molecular sieve column I want to run at 70 degrees and I want the
inject time to be 40 milliseconds.
Something we didn't talk about was what that
means and why it's reproduceable.
There's two constants that make a reproduceable injection.
One is, and both of them are set in the software, one is the
column pressure, the other is the inject time and I'll tell
you why those two combine to make a reproduceable injection.
My mouse is stuck.
Let's open this up a bit.
My backflush time just from my experience, I'm going to set at
eight seconds because that way it should be cool enough so it
won't allow the CO2 to come onto mole sieve column.
We might lose, at this low temperature, we might lose some
of the CO but we'll only have to play with
that and find out for sure.
>> male speaer: [unclear dialogue]
>> male speaker: Air analysis but I'm
going to try and get them all in one.
I want to get everything.
I want to get hydrogen, oxygen, nitrogen, CO, and methane.
So, if we can find some methane, we can find out whether this is
going to work or not.
There's no reason to have multiple methods because the
whole idea is to separate out the compounds and be able to
tell based on that what the concentrations are.
The detector is on.
That just tells me that filaments are on and the thermal
conductivity detector.
The TCD limit check is on.
All that tells me is that if I shoot a big huge sample in and
it's going over range, it reduces the range to half so
that you don't get a big electrical or temperature shock
on to your filament for the TCD.
We're going to invert the signal on this one because we're
running argon and what if I don't, then all
the peaks will be pointing down.
I'm going to run in static pressure and
I'm going to put it at 22 PSI.
This is never needs to be messed with.
As far as the acquisition channel, I always run a sampling
frequency of 100 Hertz.
I don't know why anyone would want to stop, not do that, so I
really don't ever change it.
The run time, I'm going to say two mins at 120 seconds per mile
just so I can see everything.
It won't be, no we've only got air, let's just do 60.
There's no reason, it'll get everything off in 60 seconds.
So, that's our first channel.
And that's, down here it tells you that this is the one that's
running argon and it is the mole sieve 5A
which is the molecular sieve.
The next part.
The other channel, it's a Pora Plot Q.
I'm going to run it a little bit hotter at 80 degrees.
Again, my inject time I'm going to put at 40 milliseconds
because we should be able to see the
atmosphere of C02 when we run this.
Detector's on.
Detector's limit check is on.
I'll run pressure at about 18 PSI.
Acquisition the same, 60 second run, so
that it matches the other.
And that section is built for that particular part of it.
At this point, I'm going to save this.
Flie, method, save.
And I'm going to save it as Analytical Method, so that
you'll know which one to use in the future.
Now, I'm going to download this method into that analyzer.
The reason I want to do that is I want to go ahead and start the
columns raising up.
The thing about chromatography is it
doesn't like being turned off.
Any chromatograph doesn't like being turned off.
You're better off letting it run all the time.
You're going to use maybe 15 mils of gas a minute,
milliliters of gas.
In that case, that thing ought to last a
long long time, like months.
So, just leave it running.
It doesn't take that much power.
Okay.
So, I saved it.
I did two things there.
First, I saved the method.
I saved it in this method.
I saved it that way.
But, I also did something else that's pretty important and that
is I went to the control section.
Everything that's happening on that analyzer right
now can be seen through this control section.
If I'm going to make an injection, if I'm going to
download a method, if I want to check and see what everything
is, that's where I go to look at it.
So, I downloaded the method.
When I downloaded the method, it started bringing the
temperatures up.
And I know this because I can go to instrument status and look at
it and now my temp is 70 and we're coming up to it.
My temp is 80 and we're coming up to it.
We've already hit the pressure points I need.
At the end of this time it's going to, everything will turn
green and it'll be ready to make an injection.
>> male speaker: Go ahead.
>> male speaker: [unclear dialogue]
>> male speaker: You're preparing it.
You're bringing it up to temperature.
You're not running.
But you shouldn't need to run all the time.
You don't need to download it and tell it to run a sample.
You just need to tell it what temperature it needs to be at so
that it'll be ready when I want to make an injection.
So, I'm bringing it up.
Now, the common parts.
There's another thing that we control through
this called the sampling time.
A sample time is in seconds and it's how long the little suction
pump inside that analyzer is going to run
and I'm going to do it for 15.
Stabilizing time is in seconds as well.
That means once I hit a ready state, I'm going to stabilize
for about five seconds before I let you make an injection.
That was all under the tab Agilent 490 Micro GC Method in
the Instrument Setup.
Baseline check, don't ever work with that.
I usually remove this.
It's just so you can start a run and monitor the baseline for a
certain period of time.
If you just want to see if things are jumping around, maybe
there's a pressure problem on the analyzer and you notice
peaks that are coming in that you don't think they're real
peaks, just monitor the baseline and see
what it does for a while.
Trigger is important.
This will never run unless it is in none.
The only reason that, well that's not exactly true.
Did you have a stream selector valve that
you wanted to put on here?
Now for some reason, I was thinking you was.
A stream selector valve will send the signal
out telling that Micro GC to run.
So if you have a number of different lines and you're
switching between them, it'll switch over to one line, wait,
and send an external signal out.
Other than that, none, that way when we hit "Go" here, that
makes that analyzer work.
>> male speaker: [unclear dialogue]
>> male speaker: You have a gassifier.
>> male speaker: [unclear dialogue]
>> male speaker: Well if we're going
to do air why don't we run the pump just pull
it out of the air.
>> male speaker: [unclear dialogue]
>> male speaker: Even then you wouldn't want
that because you just make your injection and while
it's, I'd still probably run the pump, even
though you're just doing a syringe injection, how are you
going to do a syringe injection on this I need to understand
that a little later as well.
>> male speaker: Um we don't know
[unclear dialogue]
>> male speaker: He's kind of, Burt's really
good at that, Burt's a good service engineer.
>> male speaker: Go ahead with your system.
>> male speaker: So what I've done so
far is I've told it, I want to run this system at
this temperature that's all I've really done.
And at this point, I don't need that open, I can minimize this,
and I'm just looking to see I'm at temperature and I'm ready to
go so let's run a sample.
Running a sample is pretty easy.
I go with icons when it comes to this because this little "Go"
icon for some reason didn't want to have
it's name, that's a single run.
Okay?
If I click it, I'm going to tell it that I actually want this,
this is an air sample, I'll put an underscore.
There are things that you can put on here like date and time,
and an increment number.
I usually put underscores because all the numbers run
together if you don't.
I'll put an underscore and I'll also put a date and time.
So we'll do probably the same thing here, and you did almost
the same thing I did, the ID would be "Air" and whatever
increment number this happens to be, but not the date and time,
that's the sample ID but on the data file
I want the date and time as well.
So I'm going to put an underscore and the date and
time, because I like to date my data files.
Also, this is the default, it goes into a default subdirectory
called "Data" but you can also put it into one for the date, so
let's put one in for today.
So we put a slash in there, and I usually do my dates like 2001
underscore eight underscore, what is it the 31st?
Thirtieth, this is ready to make an injection at this point.
Let's go ahead, just for the fun of it, and say you want to do
five of these injections instead of just one.
So you can do replicates this way.
So if you're going to run the same gas over and over again,
you can do replicates this way and you
can track it by the time.
So maybe that's a good way to look at it.
This is also the screen we'll use whenever
we calibrate but we'll get to that later.
So we say "Start."
Okay that file, that folder doesn't exist so
I want to create it.
Current method has changed would you like to save it?
Thank you for telling me that.
Yes, I do want to save it.
And then, we should be able to look at these two channels of
data, where's my other one?
The suction pump kicking in.
At the end of that it made the injection.
And it's putting both of these on one run, on
one screen which I don't like very much.
I'll break this up and put them on two separate screens.
>> male speake: [unclear dialogue]
>> male speaker: Okay well you can
have it that way, it's easy, I'll leave it the way
you want it.
You can blow these up as they're coming off,
and you can see that there's my one peak.
And I need to take a look inside this box.
Because I think that you have argon
running to the wrong modules.
Yeah, it should be running to the mole sieve,
but it's running to the Pora Plot Q.
There's no reason that these should be negative, I inverted
the signal on one channel, on the mole sieve,
so it should have been up.
I'm going to stop this because I don't want to run this anymore.
And you might want to stop at this point because I'm going to
have to take that analyzer apart.
>> male speaker: [unclear dialogue]
>> male speaker: We could do that, but
we need to check that.
>> male speaker: [unclear dialogue]
>> male speaker: I did as well, on this one.
If you go into the instrument setup, you go and look at the
method I inverted, the one on channel one,
channel one is a mole sieve.
The fact that I inverted it and it's now going negative
means that it's got helium running on it.
Which is not critical, it's not good, because the TCD voltage is
different when you're running argon or
when you're running helium.
If you're expecting to run helium, it sets
it at 15 milivolts.
And if you're expecting to run argon, then it sets it at 10, so
you lose sensitivity.
I don't think we've hurt the analyzer at all because if you
go and look at that data file even though it's inverted, we
can go in here and look and we see that the peaks are nice and
pretty, the baseline is good, what we're looking at is oxygen
and nitrogen on the one and just a deposit air peak on the other.
I can blow this up, I don't know why they put both of these on
one channel , if we blow this up we can even see that this is
going to be CO2 at about 400 parts per million.
So I know where the CO2 is coming out as well.
So let's get that fixed and otherwise I don't want to run
anymore samples.
Okay so this is my number carrier right?
That went through here?
It's coming through, it's coming through here.
Going back into this guy.
It doesn't make a lot of sense to me that this would be the
number one module, number two module.
The number one carrier is going to this one not this one.
Was it not an easy call for Burt, he bought this dang thing.
I've gotten to lately where I pull them apart.
>> male speaker: So again argon
channel one is argon?
>> male speaker: Channel one should be argon.
Right now, it's not.
So if you've got a sharpie, let me just mark it
on the back of the analyzer.
Now I would recommend putting a valve on both of
these, so you can shut them off.
There's a couple of reasons for that.
Number one, it's easy to flush these guys out.
Just by definition the way this works, you know it's got that
little dip tube in it, so it's got a little bit of air in it,
so I always flush it two or three times.
It's not as important on yours I think.
>> male speaker: Actually to tell you the truth
I've had a hard time finding parts.
>> male speaker: It would be under a
swedgelock go to a swedgelock site.
A lot of people use...
>> male speaker: That's okay, but maybe
before you go we can get the phone number from you.
>> male speaker: Yeah, a lot of people use
maybe a little swedgelock like this guy.
And some people use ones like this guy.
Like, so that's a hoak I think.
Um, I got to turn your gas off though,
have to disconnect everything.
While I'm taking it apart and talking about it, the carrier
gas ought to be set at 80 psi plus or minus like five percent,
I think the spec says plus or minus 10,
I'd say plus or minus five.
And the reason is that it's always used to drive the
sullenoids so they have to be within a certain range.
Let me make sure of this.
The other thing that we did that you notice is we actually have
two pumps, and the reason we do that is sometimes when you're
pulling argon or helium from two different channels, especially
if you're doing hydrogen, plus helium actually comes off at the
same place [unclear dialogue] So we fixed that a long time ago.
This is operating really well just from the peak shapes and
how everything looked, we just need
to get it configured correctly.
That's how it goes back together.
I have a tendency now to drop these screws inside the little
cabinet and then have to take it all apart again so I don't want
to have to do that.
How high up in the hydrocarbon range do you think you might
have to go doctor?
>> male speaker: Not very high.
>> male speaker: Just the C3s probably?
That's good.
Pora Plot works very well for that but if you wanted anything
higher I'd want to go with a different kind of a column.
This one is a 490.
So they're familiar with running it then?
>> male speaker: They are, I'm not,
I'm learning from scratch.
[unclear dialogue]
>> male speaker: So we wait for it to
come back to ready, the first thing it's going to do is go
through the..
>> male speaker: Just push that.
>> male speaker: It goes through these
Christmas tree lights, while it's getting ready.
At the end it will start flashing two green lights,
that's when it's in a boot peak, that's when we could go through
and set the IP address on it, and then it'll come to ready.
First thing it does is do a flushing of the system and in
fact we'll go and open up the software, we can tell whats
going on on the analyzer.
So we'll go to "Control," there's a communication error I
have to clear up first.
Probably didn't want us to talk through it while it was going
through that initial start up.
We'll take a look.
Okay so we go to "Control" because anything we want to see
on the analyzer we do through control.
We go to the instrument status and it says we have a
communication error because we don't have a cable plugged in
and we don't have bluetooth yet.
That would make it a lot easier.
Now it should work.
No matter how hard I try.
I like simple stupid mistakes because
they're easy for me to fix.
>> male speaker: [unclear dialogue]
>> male speaker: That's the sollenoids
that are going through their diagnostic
clicks, it goes through a check of each one of the sollenoids on
all the nuematics.
It also goes through a flushing state where it's opening them up
and flushing all the gas out, which is good considering we've
got the wrong gas going into it.
We may have some little, there may be a few things that we see
in the software or in the chromonogram right now that
won't look normal, I won't know until I run it.
But we'll take a look at it and see.
It tells you that it's in the flushing state.
When it's doing that flushing, the detector is not on, that's a
good thing because we turned it off because we had the wrong
carrier gases running to the wrong systems.
When we get through with this we run it with no change in the
method and it should look right.
As far as your view, if you wanted an overlay you can
certainly leave it that way, but I'm going to do it in tile right
now because I'm a creature of habit, and if I don't I won't
know what I'm doing.
It's kind of easy to fix these things, I know it seems like
it's really busy but whichever one is on top, towards you, so
in this case the Pora Plot is towards me, I can right click
and say "Tile Horizontally" and I can see
the two different channels.
Again we'll fix this and we do see that we're getting our peaks
out in time, and we're getting all of our peaks, this would
have to run longer for, to do methane and CO which would come
out here towards the end.
But we've got acres of separation between oxygen and
nitrogen, so I'm going to raise the temperature a bit.
And I can do that while it's going
through that flushing state.
I think, let's find out.
So on the mole sieve, which is the one we were looking at, and
it says at the top, I'm going to raise this to 90 degrees.
And save the method.
Save method.
And download the method, and I think it's going to tell me that
it won't let me do it because it's in a flushing state.
Ah, maybe it did.
Yeah, it's still flushing, so it didn't let it download.
>> male speaker: [unclear dialogue]
>> male speaker: Actually what I'm going
to do by increasing the temperature I'm
pushing all of the peaks closer to the front, and that's going
to have the effect of pushing to go to the oxygen and nitrogen.
The theory of chromotography being that there's an affinity,
in a mole sieve it's not so much an affinity but if it's got five
extra holes in a molecular sieve solid and the gases go in and
come out at different rate, so hydrogen is almost unretained,
it goes through very quickly, so it's the first one out.
The next one is, of course oxygen and then nitrogen.
The things that it effect how quickly it goes through that 10
meter capillary is temperature and pressure.
>> male speaker: The hotter it is
the faster it goes.
>> male speaker: The faster.
The faster it comes out.
The higher the pressure the faster it comes out.
Pressure, we use pressure because it's easier to control
pressure accurately than it is to control flow, at least
economically so we set pressure, it's a constant pressure, you
don't have to change the pressure, so it's always coming
through at the same speed.
And it's still going through that flushing step, probably
because we had to switch the two carriers, and it wants to make
sure it flushes it all out.
This is a pretty good diagnostic to look at, one thing to know
when a detector is going bad is you'll see that the autozero
will start going very very high, over 200 to 300 mils.
We'll see what it is when it comes on, we can't read it until
the detector goes to on, which takes a while when it's going
through this flushing stage.
Any questions right now would be a good time because there's
nothing else going on.
>> male speaker: When you talk about the
syringe, are you're going to explain later
on how we will go about that process.
>> male speaker: I'm wondering why you
want to do a syringe.
To me a Micro GC is a gas analyzer, by definition
you can't shoot anything but vapors in it, you'd have
to have a gas tight syringe with a valve on it.
Most of the times, gasses are a little bit pressured,
and if not, I've got a pump to pull it in.
If you buy a standard it's going to be under pressure and you
just need to make sure that you never put more than 15 psi on
it, hook it up and with the suction pump and that positive
pressure on the back you get very nice reproducable results.
I guess it's because your sample and how much
gas you're going to make.
Usually people make a syringe injection when they're limited
on how much sample they're going to have.
So for a lot of bio reactors, a lot of people who are doing
really low fermenation work, they only have 50 mils of gas or
something like that, so they want to limit it,
how much they got going in.
And I don't know if that's going to be the case with you.
>> male speaker: [unclear dialogue]
>> male speaker: Well you didn't buy
a syringe injection system, I mean we do sell one.
This is a standard setup that we do for most gases.
We also have another one that would add a valve so that you
can switch back between the two and it has a pressure relief on
the back of it, and then it has two little capilarys that come
over and then you can inject them in front of the analyzer
and we can either put a lower lock here or a septa.
What Bert was talking about was putting a T inline maybe and
doing a syringe injection and I think he got
your part numbers for that.
There's caution when you do that, what you need to make sure
that you, you'd have a T, I can draw a picture, you'd have a T
coming in, and then a short capilary where you could put a
septa on the end and inject into that.
But you're going to have to have a valve and you're going to have
to have another valve, because you're
going to have to isolate the two.
And the one valve going into it from the sample that needs to be
pulled or has pressure on it, the standard system has to be
very very close to where that T is because otherwise you're
going to get part of that sample will always be there even when
you're injecting and trying to go past it.
If they have to do it, fine.
It's not the way I would do it.
I would go with, I would go with some sort of, depending on the
type of flow you had, or how much flow you had, you would,
should always have enough flow to get through this system.
>> male speaker: [unclear dialogue]
>> male speaker: Absolutely, even, or maybe
even a tevlar bad or something, if
they're limited on samples there's pretty small tedlar
bags, not real small, like 100 mil or so, or
200 mil I think they are.
I'll talk to them about it when they're here.
>> male speaker: [unclear dialogue]
>> male speaker: No.
Tedlar bag, you might,...how big are we talking when we're
talking limited sample, how big are we talking about?
Do you know?
Well I'm thinking on a bio, the fermenation process.
Don't know?
For years on the gassifier you won't ever use it, there won't
be a syringe injection.
>> male speaker: [unclear dialogue]
>> male speaker: 10 mil's going to be
very hard to do when you think about, the
thing, the loop on the injector is very small, one mil, actually
I think it's smaller than that, I can't remember
my numbers right now.
But there's all the tubing that's upstream of that, and
what you want to do is overfill that loop
about at least five times.
Well, there's your 10 mils gone quickly.
And I've got a person doing just that, trying to do it
with 10 mils out in California and she's
not getting reproducability at all.
Now I think she may be doing something wrong which is why
I've got to go out California in a couple weeks.
But I have a person at the USDA that's doing, who has the
configuration with the syringe injection like a septa in the
front, on his system I'm using about five mils of gas everytime
I do it on a gasified syringe, but again he's got very tiny
capilaries coming from here up into the back and through a
pressure pop off that goes into it and to the injectors.
This still says it's flushing, which maybe because we took all
the pressure off it, I'm going to reboot just to see if it's
really flushing or if it hit a diagnostic step.
Should have a communication error, it's going
to give me a little break.
Instrument is in the flush cycle, okay not anymore.
I just turned it off.
>> male speaker: [unclear dialogue]
>> male speaker: It's a tedlar bag
but if you're saying that they're limited to
like 10 mils, that's going to be too big.
There are a number of different bags that you can buy if you
just go search under, if you Google "Air sampling bags" I
can't remember a name of a company right now, it seems like
one's called gastech.
But you should be able to search it pretty easily.
And it has a little valve on it where you can push gas in, where
you can fill it up slowly and then you can just take a piece
of tygon tubing on the back of this.
I may have some with me.
I keep some with me in case I'm ever doing that type of work.
And I'll put it on the end of that fit 16th inch fitting, this
ones kind of dirty, and the other one would go under that
tedlar bag, you open up the tedlar bag and it suck, keep a
little bit of pressure on it and it'll pull it right in.
>> male speaker: Yeah some people
call it a balloon.
>> male speaker: A balloon.
Yeah balloons are a little permeable.
The nice thing about the gas bags is that they're made out
of, I think they're made out of a nylon material and they don't
let anything through.
>> male speaker: Let me see if I
can talk to this guy again.
>> male speaker: Hit that one.
Okay.
I think it's going to tell me it's got to double click it.
Should be opening.
It's flushing again of course because I just told it to.
Any other questions while we're waiting.
Analyzer likes to be sure that it goes through its diagnostics.
Everytime you restart it, it goes to this default setting
which is 30 degrees and 7 psi.
Which is annoying because if you have a method set with 150
degree temperature on it, all you did was turn the power off
and back on and it's going to go down to this go through a
flushing step and all your temperatures are going to drop
off and you've got to wait for it to come back up.
I'll look at something here.
That's one reason why you have such pretty and big peaks here.
You'd know it the first time you'd try to run hydrogen on it
because there wouldn't be any.
You wouldn't be able to see it.
That's probably a little bit of helium that
was there from the other line.
I'm surprised we don't see some argon, right in this area.
The software is actually pretty easy to use, it's all on one
screen, there's not a lot of clutter.
Alright, where are we?
Still flushing.
There's a little bit.
It's pretty well documented in the manual, you'd have to read
the 170 page manual which is not so fun.
I was with Varian but not when the acquisition happened.
I started with Varian in 1988, and worked for them in the
inside sales group and in tech support, and then became the
product specialist for the Micro GC when we bought Chrompack the
previous version of this and the 4900.
I had left and gone to ABB, which is
more of an Engineering firm.
Was there for about five years just before they realized that
when they kept this analyzer, which was an analyzer from
Varian that they didn't keep anybody that knew anything about
it, not in the U.S. anyway, certainly at the factory.
So they were looking for a product specialist and some
application engineers and asked if I would
come back and work on it.
It actually happened in November of last year is when it was
finalized, it's when they actually folded the two
together, but they'd been working on
it for about year before that.
And they divested themselves of the Varian GC, the Benchtop GC
line, they sold that off to Brucker, but they kept the
Varian Micro GC.
It's the reason they didn't know anything about it.
It shows it's ready but it still shows it's flushing so I'm not
quite sure why it thinks it's in that flush cycle.
I want to see if, when I turned it off I might have left
something running.
In the process is that I actually needed to shut down.
I've got all those service host open.
The services are all open up on it.
I think probably what we'll need to do is..
Yeah that ready light came on and went off.
There we go it just came up.
Yeah and it's not now because it's starting to
reach the temperatures.
And as soon as we get back up there we'll run another one.
Again a number of different ways to do it, you can either do it
from control single run, it gives you the icon so that you
know which one to use, I use the icon so I'm
going to run the icon again.
>> male speaker: [unclear dialogue]
>> male speaker: They haven't gotten any
less expensive no.
The real savings in the Micro GC is not so much, the engineering
is still the same, the electronics, in fact it cost
more to make the injectors so that's one of the things.
The real savings is the amount of gas that you don't use, and
the speed of analysis because on a bench top system to do this
same analysis the fastest I could do it would be somewhere
around maybe 12 minutes, on a standard gas chromatagraph.
So we gain a lot in speed and productivity.
>> male speaker: [unclear dialogue]
>> male speaker: So hopefully this time
the peaks will go in the right direction.
The two pumps kick on.
It's pulling a sample, in this case just air.
>> male speaker: Did you decrease
the temperature.
>> male speaker: Yes I did so they
should be a little bit closer to the front.
Not a lot, I only changed it about 20 degrees.
One thing you'll notice is this shift in the baseline.
This is normal.
What's happening is, the way that the system operates is
there's a reference gas which is going through one side of the
thermal conductivity conductor, and then an analytical.
And it's always measuring that reference
giving you a constant current.
And the other one whenever another compound comes through
it has a different thermal conductivity it
gives you a signal.
Since they're matched at the beginning, once we do a
backflush, the way it does a backflush is some of the flow
goes away to backflush the sample to a vent, when it does
that it shifts a little bit from what the
other reference signal would be so it's a little offset.
It's just a little bit of an offset.
So that's more like it.
So now, I've got, I forgot I set this up to run five of them.
It's really not any reason to, let's just stop.
I'll change that so that the next time I do it I don't start
five runs, I'll put it back to one.
So I'll open up a file, oops sorry, data file,
I'll open that last one that I ran.
See if it's running.
Told you not to run, stop all of them.
Thank you.
Open up that data file that we just ran.
Which is the last one in time.
And now I can start identifying the peaks and telling it what
the integration parameters are of the chromatagram.
This is good enough for what we're going to be doing and good
enough for the work that you're going to be doing in the future.
Again, we see the CO2, which is the atmospheric CO2 at about 400
parts per million.
This other peak out here is water in the air, I'll save this
method, I could probably heat this one up
as well, I may do that.
The propane products would come out after that, and what I may
want to do is go ahead and make it longer so
when you run propane you'll be able to see it.
So since I know what the elusion order is and I know that that's
water because that's what water looks like on a chromatagram,
it's a big tailing peak.
I'm going to go an change the method in the instruments setup,
and I'm going to run it for 90 seconds as opposed to 60.
I'm going to save that method and I'm
going to download that to the analyzer.
But, that doesn't stop me from doing this.
Well we'll do one so that it's got the right end time on it and
I'll show you some of the things we do as
far as the integration events.
So we're going to run another one, just like the other one,
only this one's going to be 90 seconds long.
At the end of that then I'll go through
and set the integration events.
The software was developed originally to run Mirco GCs, the
Scientific Software Incorporated was the name, SSI.
Then the guy who wrote it, who happened to work for MTI which
was the first Micro GC out there, split off and he said,
"You know that's fine, I'd like to take my
software with me when I go."
And so he kept his software and started developing it, and it
became a client server type full blown chromotography data system
so that you could hook up 200 different analyzers and 15
different servers and pull it all in
and access it from anywhere.
Because it's like that, the base software itself has these
parameters set it in that don't match up to Micro GC anymore,
and one of those is in chromotography
how do you define a peak?
That's always important in any chromotography software, and the
way you define a peak is you establish whatever baseline is,
whatever your regular threshold is, and it's set in peako amps
usually, and my baseline's going to fluctuate this much.
Okay, that's my threshold.
So I want my threshold to be higher than that otherwise it'd
just see a whole lot of trash.
Then, when it comes off of that, if my baseline starts to move up
from that, that could be a start of a peak or it could just be a
baseline drifting up.
So the second parameter we'd have to set would be how wide
the peak is, how wide we expect the peak to be.
If it comes down within that certain amount of time, ah,
that's a peak and I can now integrate from front to back.
Otherwise it's just a baseline drifting up.
So the two things you have to set are
the threshold and the peak width.
Well the threshold and peak width on this is set for no
chromotography that I know of because it's set for .2 minutes,
yeah .2 minutes which is 12 seconds.
There's no peak ever, on a Micro GC, that's 12 seconds wide.
The whole chromatogram is 90 seconds wide.
So we have to change a few things.
In the method, the instrument setup is the first thing that we
did, so the most obvious next thing we have to do would be
integration events on the chromotography itself.
What I'm going to do, because this is method development, is
I'm going to say I know that this is not going to see a peak
until about out here because this might be a little bit of
helium here, and that means that hydrogen is going to come out
somewhere in that area.
So I don't even want to look at anything up to .35 seconds.
Let's fix the peak width first, instead of .2, instead of 12
seconds let's make it 1.2 seconds, that's how quickly the
peak would have to start coming down for me
to say that it's a peak.
And threshold I can set graphically.
But the first thing I want to do is tell it I don't want to look
at this stuff in the front of it, I want to turn the
integration off from zero to 0.35 because
that's about right here.
And I'll say, save the method.
And I can analyze it, and see that it doesn't even
start looking for anything until about there.
The next thing I want to do is set my threshold and this can be
done graphically, in this case I'm going to say that I want to
set the threshold.
The threshold and the baseline should be about whatever that
threshold is, and it tells me that it's 337
the software will calculate for me.
Well, I like to go a little overboard on it so I'm not going
to make 337 I'm going to put 1000 in there, and then I'm
going to analyze again and sure enough it still finds some peaks
there that I don't want it to see.
So 1000 is not good enough for what I want to do.
I want to put 2000.
Let's say analyze.
>> male speaker: [unclear dialogue]
>> male speaker: Right, I was just
finding a flat spot.
>> male speaker: How do you relate this to
2000 or 1000, 1000 is milli, or micro.
>> male speaker: I think it's peako
amps but I'm really not sure.
It comes up, and the one that shipped as the default is 50,
50 is obviously wrong.
10,000 is too high because it's taking off some of the peak that
I think is here, and by the way this baseline looking like this
is because we had the wrong carrier gas going on.
This is going to, we'll bake it out again tonight overnight, but
we'll make this look a lot better.
So I'm thinking maybe I'll split that, 5000, this is just
experimental until I get it to where it's drawing my peaks
about where I want them to be, and it seems like it's kind of
drawing them there now.
Although it's finding a bunch of just in there
that should not be there.
This stuff up in here shouldn't even be there.
And a lot of that has to do with, we'll probably need to
flush it three or more times, I'll do that
before I leave there today.
Okay so that pretty much defines the peaks that I want to know,
which is oxygen and nitrogen, that's all I can
really look at on this channel.
Once I have these things set as far as my threshold, my
integration off so it's ignoring anything up to here, until I can
see maybe a hydrogen, which I'll have to shoot later.
Then I can tell it what these two peaks
are because I know that.
What I'll do is, I want to add multiple peaks to the peak table
also this is graphics down on the bottom, and you can put your
cursor over and it kind of defines it for you.
You can put one peak or multiple peaks.
Or, I could go to the next part of the method and I could type
them in, I like to do them the other way and the reason I do is
because it also puts in what window you should expect based
on the width of the peak.
So if I go to "Define the Peaks" I want to define the peaks
between here and here.
Just on the front and back of those two peaks.
And it dropped those into my peak table with their times on
it, it doesn't know what those peaks are it just says, "Here's
two peaks, name them."
The first one is oxygen, and the second one is nitrogen.
Alright, and I'll analyze again, and something I forgot to do
earlier, I'll go to the annotations and I want to put
the name of the peak and the retention time of the peak and
say, "Apply it to all channels."
And say "Okay."
So now it says, "Well there's a bunch of other stuff on here
that you didn't name, like this is a peak and we don't know what
the name of it is."
It's really not, it's a bunch of stuff on the baseline.
But this is oxygen and this is nitrogen.
And I'll do the same thing for the other channel.
The thing to remember at that point is though, there are
integration events for each individual channel, and the one
that I was working on was channel one, channel one.
I've got to change this now to channel two, and if I went and
looked I would see that the integration events are defaults
again, which I don't like.
So let's minimize that guy so we can get the right one up here.
Okay so now I have this chromatograph that I'm working
on, and I can analyze it, sure enough that didn't do a lot of
good, but it does kind of define my peaks a little bit and I
think it's because it also has a noisy baseline based on the
changes that we made.
That's pretty good though.
Now in this case, I don't even want to calculate that peak,
it's the air peak that I don't care because I actually have the
components of it broken apart on the other channel.
So I want to ignore any integration up to the time when
maybe methane would come out, which would be about here,
but certainly CO2.
So we're going to put it out here at .5, we're going to say,
"Don't look at anything up to .5."
I can click on this cell, there's a pulldown, one of them
is called "Integration off," I have to give a start time of
zero, I have to tell it when it's going to end, well it's
going to end at .5, and I analyze, this little analyze
button, sure enough it ignores that peak.
Integration off.
Now I have two peaks here, I'm probably going to go ahead and
tell it that's water so that it'll not that it's a water
peak, so I want to add my peaks again.
Right click here, well I don't right click, but I click this
icon, it says, "Where do you want to start
looking for peaks?"
We'll start there.
"Where do you want to end looking for peaks?"
Let's stop there.
Now if I go look at my peaks in groups, I have two peaks named,
the first one is, I'm just going to put CO2 as an abbreviation,
and the other is water.
Now if I analyze again, it puts their names there as well.
And that's as much chromotography as I can do on
here, there's not enough out there for me to see anything
else, I can't see the CO2 that's in the air because it's far too
small and we've got to let that cook out a little bit.
The next thing that you'd normally do on a system would be
to calibrate these peaks, but we can't really calibrate the peaks
because we don't know how much there is, and we can guess that
there's somewhere between 360 and 400 parts per
million of CO2 in the air.
I think it was 320 when I was growing up,
it was down around 300.
I know it was 320, 340 when I started in chromotography and
now it's up to about 400.
We certainly don't know how much water is in the air so we can't
quantitate that peak, we'll just name it but we
won't ever say how much is there.
On the oxygen and nitrogen we can kind of do those,
we know what the mixture is there.
So if we go back over to the mole sieve and we call in that
chromatogram, well let's just close a bunch of this, that's
just kind of busy.
We can save this method that we've added
those peaks to by the the way.
But if we go to, that's not it, this channel.
I can kind of calculate these pretty close, I mean close
enough for plus or minus five percent probably.
If I go to the peaks or groups,...I got to go over and
tell it what level it is, and it's got a lot of busy things
here that you're not going to need.
The thing you need to remember is that you're going to have to
work with levels, and the level of oxygen that's in here is
about 22, let's go 22.0, and the amount of nitrogen that's in
there is 78.0.
And we'll say, "File," "Save Method."
Now I can calibrate the system and it will tell me that the
next time I run one that it'll calculate what this is.
So I want to go and next to where analyze is up here,
there's an icon called "Single Analysis Calibration," this is
all here by the way, and analysis single calibration I
just run on icons.
So I go to this guy, and it says, which data file
do we want to use?
And I'm going to use the one that's
open right here, this air.
And I'm going to calibrate, and I'm going to calibrate my first
level, and I can calibrate 1-10 because there's
10 different levels there.
And I want to clear the calibration just for this level,
because if I had other levels, I don't want to throw that stuff
away just only this one.
And I'll say, "Okay that's what I want to do let's start."
And it now says that if there are this many area counts,
that's 22% oxygen and if there's this many
area counts there's 78% nitrogen.
And I can look at a report on my external standard, because
that's what we're doing, is an external standard, and it will
tell me that I just calibrated this and that these area counts
correspond to 22 and 78.
So now I'm going to run an unknown, it's going to be an
error, and it'll calculate, based on this,
what it thinks is in the air.
It should be pretty close, let's find out.
>> male speaker: [unclear dialogue]
>> male speaker: Yes, you can do
it all at the same time.
I like to generate a data file because I like to look at it and
say, "Okay this looks pretty good."
And a lot of times too if I'm doing a calibration of different
calibration gases I'll run two or three and if they're exactly
on top of each other I don't use all three and average them,
they're all the same anyway, I just take the last one,
and say, "This is my level."
And I calibrate it.
But you're going to have to get calibration gases for all the
things you want to see.
Another thing to talk about while this is running because a
lot of people get confused when they think about calibration.
You're probably okay doing your calibration with 100% gases
because it's 1% plus or minus kind of thing.
Your calibration gases that you use should make sense, if I'm
going to do, analyzer specification is plus or minus
.1% right, so if I'm going to do a calibration of a particular
compound, and I'm going to look at a 100 parts per million, and
the range that it might actually happen is 100 parts to 1%.
Then if I do 100% as a gas and just draw it through zero, that
might be accurate, maybe not, this one should be fairly
accurate, but not really accurate.
If I really wanted to do 1% and this was my range, 100 to 1, I'd
get a calibration gas that was probably about 10%.
So I'd do 10% force it through zero and then I'd be looking at
here and that's a fairly straight line, and 1% would be
valid, and even 100ppm might be valid, pretty close.
It'd be better if I had a 5%, and that's because what you're
looking at is 5.00, okay well my reproducibility is somewhere
around here, that's 1000, that's 100, so 10 ppm is my limit by
doing an external standard by what I could
expect the analyzer to reproduce.
So I don't want to get any better than this, I certainly
couldn't use 100% because that would be somewhere around here,
which is 1000 ppm, should be what I expect
my detection limit to be.
Reproduces to .1%, so about 1000 ppm.
So don't do 100% of something and expect to
get decent numbers in the ppm range.
>> male speaker: [unclear dialogue]
>> male speaker: Whatever you're going
to look at, that's absolutely right, but higher.
It should have a similar composition to what you're going
to look at, at it's highest test range.
The other, because the other side of that equation is, okay,
let's say that I know that I'm going to be looking at 100%, or
100 ppm to 1% so I'm going to make my top standard 1%, well in
reality, that 1% is real, and anything else that it calculates
out here is a guess.
I mean it's a valid guess, it's probably a pretty good guess,
but it's a guess because you don't know for sure it it's
still linear or beyond that.
Okay so I go now and look at an external standard, and this
calculated the area percent or the area counts
under those two peaks.
I'm assuming they're pretty close, in this case it's telling
me there's 21.7% and 77.1% so it's not exact but it's pretty
close in its instant range.
The reproducability when you're pulling a sample through that
doesn't have any pressure on it, is not as good as it would be if
you had some pressure on it, either from a bag or flowing
from your reactor.
The important things is, never get above 15 psi because you'll
blow the injectors up.
So your upper limit is 15, the other thing to remember about
the injector on the Micro GC is that when the sample, when it's
not sampling, it's deadheaded against the injector and when I
say against the injector, in this case it's a sillica chip
with a little pressure point.
So if you've got 42 pounds of pressure on your reactor, even
if you're flowing one mil, it doesn't make any difference, if
it's sitting there, it's eventually going to come to 42
psi and it's going to blow a hole in that injector.
So you have to keep it below 15.
And I don't know if yours even has pressure, I don't know the
process itself.
>> male speaker: [unclear dialogue]
>> male speaker: A little bit of a vacuum.
Doing partial pressures it's really hard to get any kind of
producability on too, because the vacuum pump works the same
but if it's at .95 atmosphere and then it's .9 atmosphere
there's a different amount that it's pulling in to the system.
So your reproducability may not be real good, you might like to
get a little bit of positive pressure somehow.
That might be another reason for a syringe injection or for
having a gas fill into a bag, like a tedlar bag and then
maintain a little bit of pressure on it.
Any other questions?
It has some built in, the software has some built in
reports, this is one of them, this is the one I probably use
the most in gas chromotography which is
an external standard calculation.
And it's also saying, "Okay, what was our
reproducibility of one air to the next."
The total 98.9 so about 1% pulling the sample through.
Better if I had pressure, that'd be 100.
It'd be exactly 100.
You can review each one of the calibration lines, we only have
one point through zero so they're both perfect.
But it calculates what your response factor is for
both of the two analyzed.
So when you run an alone it applies that response factor to
the area count.
I can also output this results and this may be a value to you
and I want to talk about it now, because I can take the data for
each one of the peaks and I can export it as well.
So I can export the area or I can export the external standard
concentration and this is for both the two so this is only
doing one, this is only doing the one for the mole sieve so if
I wanted the other one I got to go to this guy.
And I would say I wanted the area and I wanted the external
standard concentration, and I say, save that method and if I
run another one it'll only take a second, let's do...
Do you have excel on here?
Maybe?
We'll find out in a minute.
If not, we can open it up in a text file so we can find out.
But I'm going to run three really quickly and it will do
for each one of the ones that I chose, each one of the
parameters I chose, it's going to create a file.
And that file, oh I didn't see where I put it.
Let me look at something really quickly.
I didn't tell it where to put it, so it may not do it.
In fact I know it won't.
And it didn't come up and tell me that either.
I want to stop all the ones in the queue.
As long as I wait a minute those peaks are still coming out, even
though we don't see them it doesn't make any difference.
So it's still doing chromotography,
I'm just not looking at it.
So I've got to take a little more than a minute to do this,
but I've got to go to my advanced reports and tell it the
path that I want this to go into and I want to create one on your
computer on C, but I'm going to go to C and create a
subdirectory called "Results."
Or "Micro GC Results."
Now save it, it doesn't exist create it?
Yes please do.
I want to tell it the same thing in the other channel.
I did this the other day and had two L's in results, so I want to
check it real quick.
Now then, I want to run a sample again.
Again I'll run three, now It'll go and create those files.
What else do I need to show you guys?
I guess, are you going to be running...I don't think there's
any reason without having it automated or without having a
gas coming through, to run a sequence.
If you can figure out a way to come from your gassifier into
the analyzer and then automatically sample every so
often then I would build a sequence, but there's really no
reason to if you're really only running one gas at a time.
You could just name it each time, and it keeps the defaults
in as you can see from what we did before.
>> male speaker: [unclear dialogue]
>> male speaker: Even in that case if you
wanted to run five runs, set it to five
runnings, you can set replicates and it just runs five, there's
no reason not to.
>> male speaker: [unclear dialogue]
I think, probably more importantly is that the reason
we've had such ugly baselines right now is because the
neumatics departments were filled with the wrong carrier.
So they don't flush, they flush as well as they can, but there
may be, obviously there was a little bit of helium in there.
It seems to be going away now, so now those aren't nearly as
noticable as they were before.
This guy, still got that water out there.
So the humidity is fairly reproducable in the room,
but we have no...gas chromotography is not a really
good way to do water.
Why?
Hard to get a water standard, it's very hard to get a water
that you know is reproducable in a gas.
Because even a change of two the three degrees temperature means
now it plates out and it doos out its vapor pressure is just
not high enough to keep it in a gas.
Just to show you that it actually did it, if we go to
this guy, and we go to the local disk and we go to "Micro GC
Results," where did I put that?
I thought I put it under C?
Oh, there we go.
Couldn't see it, the line was just on it.
It created a file for each one of these three,
for these four parameters.
I don't want to open them now because if I do it won't write
to it, so don't open it while it's running otherwise it can't
write to that file.
But we'll go look out in just a minute, we're already on our
second analysis.
Any questions?
Anything that's not clear?
>> male speaker: When you're looking at
the peaks, how are are you sure?
When you're saying you know that this part
is hydrogen or this part?
>> male speaker: That was because I
saw there was a little bit of helium that
was there from earlier analysis.
And helium and hydrogen have retention times
that are almost the same.
>> male speaker: So it was just the times?
>> male speaker: It's just the times,
it's the times.
And it's funny because that always reminds me, there was a
silly little movie that Sean Connery did about 20 years ago
where he was jumping around in the jungle on these ropes
and he had a gas chromatograph with him.
And the gas chromatograph he ran, one was a crushed up beatle
from inside a flower, and he ran one, and then he ran another one
had an extra little peak and he said,
"That's what I'm looking for."
And I'm like, "How do you know that?"
"How did you know that's what you're looking for?
Because it doesn't make any sense."
That's the combat.
>> male speaker: [unclear dialogue]
>> male speaker: That's right.
The only way that we would know is running an external standard.
And in this case air.
We know that there's CO2 in air, we know there's some other
things too we just can't see them, because they're
below our detection limit.
There's a little bit of neon in there and sometimes you can see
neon, which also comes around where hydrogen and helium do,
but it's very very small and it never affects the amount.
And I get asked that question a lot,
"How do you know that's what it is?
Well I look at these columns a lot, it's pretty obvious to me
what it is, but it's not to somebody
who just walks up and looks at it.
So I go through and name it, and in the future you'll now the
elusion order, so if things shift, they don't shift out of
the elusion order.
If this changes, like if this column gets wet,
these two don't flip, they just all fall forward.
So the elusion order is the same.
There are, and that's got it's exceptions to the rule as well.
When you get a mole sieve wet, you can flip
the CO and the methane.
So it's good to know, if you get a standard made up of the
compounds of interest, get them in different quantities, don't
get a one percent standard of everything, all the peaks are
the same height how do you know the difference?
If you do one percent oxygen, five percent nitrogen, two
percent methane, you can tell by the area counts which one it is.
Not just the elusion order.
Okay now if I go look here, because it shouldn't be writing.
I'm going to associate this with,
what should I open this with?
I think I can open it with, do you have office?
Oh you do.
Good.
Now where's, you don't have excel?
It's not on there yet.
Cancel that, cancel.
So in this case let's go and do it with, open it
with, where's "Open with?"
Browse, just open it with notepad or something if
I can find something.
I messed up by trying to do that.
I don't even know where notepad would be.
We can open this one with something different.
In this case you're going to want to associate
these with excel anyways.
So in this case let's go with, or word, because
word would at least be a meta file.
Oh watch, it'll come up and say it
doesn't exist on there either.
Let's do wordpad because I know it exist on there.
This is a lot easier to see when you've got it in a tab delimited
form and it's an excel spreadsheet.
But it gives you what you're looking at which is the report,
the channel, the number of records, and the external
standard concentration.
So right here is the data file on it, that's the date, and the
time, and the method, and the external standard concentration
for the two gasses or for those two.
So the first one did 21.79, 21.69, 21.72, 77.034, and 77.7.
So when you put it in a table like that you can take and graph
it, and run it over time and say this is where my switch takes
place, might be important to you later.
Anything else?
Anything?
The thing that's going to be hard to see on that is going to
be, "Okay what button did he push?"
And the only way you learn the software is to learn the
software, so we built a method, that's where we look at a method
and look at the data file.
We can also open data files offline, there's another version
that's offline, and this is how you run it.
This is how you analyze it, that's how you calibrate it.
Somebody will have to sit here and go through
those for it to make sense.
>> male speaker: [unclear dialogue}
>> male speaker: Right.
And the way that we have it set up is it does the analysis
automatically based on what we've
calibrated into the analyzer.
So you do a run, it automatically does the analysis
so you can look at the report so it's all finished.
This is still pretty messy up at the front.
>> male speaker: [unclear dialogue]
>> male speaker: Okay.
>> male speaker: [unclear dialogue]
>> male speaker: Sure that'd be great.
One thing we didn't talk about on this one because we were
talking about how you build a method and how you run a sample,
is how does a sample get into the line?
How does that happen?
It's obviously, carrier is flowing through it all the time.
It's always flowing through.
So how does the injection get into it?
And that's easier to draw than it is to say.
So from my sheet, I'll leave this with you guys so
you can kind of see it.
I break it down really simply, it's really more complicated
than this, but I break it down very simply.
If we take a sample and it's going through that little one
mil loop, and it's going out here to the pump, each one of
these has the same thing in it.
So each module has this in it.
It's got a little chip injector that's actually smaller than my
thumb, my thumbnail rather, it's about that big.
The sample, in this case air, is being pulled into here by the
suction pump and out the back.
And this is set by the sample time, and
the software, in seconds.
Once we've reached however many seconds we've got this set for,
which is 15 [unclear dialogue].
This pump shuts off, this is isolated, so the first thing
that happens is we close off one end of it so this comes to
atmospheric pressure, always reproducable
atomospheric pressure, fairly.
At that point, we isolate it completely,
we isolate this loop.
We never inject all of this, this is,
I think this is one mil.
We never inject one mil of gas into this column.
This is a variable volume injection, so how do we
accomplish that?
So actually this is where it comes into play where the
carrier pressure is.
So the carrier pressure's main purpose is to establish what
flow is going through the column, and it helps set the
time, and retention times, reduces buildup reproducibly.
But the other thing in this particular case is it actually
helps determine how much of the sample goes online.
Because this is isolated, this an atmospheric,
so nothing's going anywhere.
I bring the carrier in and I think let's go with the mole
sieve, I think the carrier's at 22 psi, and it comes into this,
so there's a delusion effect, we're bringing argon in and it's
filling up this loop which is atmospheric to 22 psi.
So if you think about your standard, it's being pushed
toward the front, and then there's the equilibration step,
the gas equilibrates almost immediately.
There's another thing that's set in the
software called the injection.
Then we set that in milliseconds.
And on this mole sieve, we're doing that for 40 milliseconds.
I'll do two pictures here.
Now, the flow, while this is setup and running, all the time,
the flow is coming through here.
Constant, 22 psi, carrier.
At the time that we make the injection, there's a little
sullenoid that allows this gas now to come through here and
fill this up and equilibrate for,
I think it's 40 milliseconds.
It doesn't take long, it's pretty set.
And at the end of that time, no I think it's 200 milliseconds.
Then we open this little valve for 40 milliseconds.
So at that point, for 40 milliseconds we let gas come
through here, and inject into the column, and then we switch
back and we're pushing it through again.
So at that point we're making an injection onto this column.
At 22 psi, and 40 milliseconds, I think I've calculated this to
be a hundred nanoliters of gas, that goes on column.
Not much at all.
One of two reasons why the detection limit is lower and why
it's so much faster, the idea behind chromotography is, you
want to put the sample onto the column as tightly as you can,
because then as it seperates it's got to look, it makes
sharper peaks.
If it's broad when you put it on, then your peaks get broader,
and it's harder to seperate them.
So it comes through here, it goes through this injector onto
this pre column, which in this case is a pora plot Q, not to be
confused with the other pora plot Q that is the other
channel, that is the pre column for the mole sieve.
Why do we use a pora plot Q, well if you think about the
elusion order that I've got over there on the pora plot Q channel
there's an air peak and then there's a CO2 peak, and then
there's a water peak.
What hurts a mole sieve?
Water and CO2.
So what I'm doing is, this is a real short column, it's only one
meter, and all I want to do is make sure that this peak gets
through but this one doesn't.
At the, and in this case at eight seconds, it's long enough
for it to go through there get this peak through, which is my
composite peak oxygen, nitrogen, methane and
CO, and hydrogen in your case, sorry.
All gets through, now for this column to be seperated the
other, there's a restrictor here that comes like this, at eight
seconds this is diverted so that
it comes through flowing this way.
Now everything is still floating this direction, for my compounds
of interest which is hydrogen, oxygen, nitrogen, methane, and
CO, but still on here is CO2 and water.
And it's going to go this way to vent.
So we never get these bad compounds on the mole sieve.
And these come over here and they separate out to hydrogen,
oxygen, nitrogen, I think CO, we never see the other compounds.
So water doesn't get on here, it doesn't affect the retention
time, CO2 doesn't get on here, doesn't affect the sensitivity.
I know it looks kind of busy, but the main thing is this
constant determines a reproducible amount of gas, you
don't have to know what the reproducible amount is, as long
as it's reproducible every time.
It's saved in the method, any change to the
method you need to recalibrate it.
If you change what the injection time is, if you change the
pressure, the carrier pressure, you need to recalibrate the
analyzer, because those two things determine
how much sample gets put on column.
This is information that I think you wanted me to
go over later but at least you've got it here too.
My handy drawing, I've probably got four more of those in here.
>> male speaker: [unclear dialogue]
>> male speaker: The critical part is not how
much you're injecting the critical part is
that it's reproducible.
What makes it reproducible is constant pressure,
and a set time.
Always does the same amount.
Any other questions?
>> male speaker: If we were to do an
injection from up there, how do you maintain constant pressure?
>> male speaker: That's a little bit of
an art, you don't push it, I just usually rest my hand on
it, just so it's got a positive pressure.
If you think about what's happening, if you don't do that,
especially looking at the oxygen and nitrogen, well analyzing
oxygen and nitrogen is like analyzing for water at the top
of a pool we're surrounded by it.
So if you don't have any in your sample and you're pulling a
vacuum on that line and there's any kind of leak, it's going to
pull it into it, maybe enough to be significant.
Where if you have a little bit of pressure on it, it just makes
sure that if any gas is leaking anywhere it's leaking out.
So it doesn't interfere with your analysis.
The other thing is I don't think the pump works that well at
atmospheric pressures and isobaric pressures.
As far as reproducing the amount on column, and I think we
demostrated that just a moment ago, because if you go and look,
well it was 100% now it's 99, now it's 98.6, now it's 99.4.
It's a different amount each time and it's the same amount of
gas going on everytime let me tell you.
What you don't do is put it in a bag and go.
The whole point is to make sure there's not
15 psi in those injectors.
For a long time when we did a standard, the capillaries are
very small inside so for a long time we didn't think about it
being dangerous, we just put a septum inject system, and then
we'd inject and we'd start seeing problems down
the way and not know why.
It's hard to gauge with gas tight syringe, what kind of
pressure you're putting on it, and if you're pushing it,
there's a restriction going against the capillary.
It won't let you push anymore than about 15
mils a minute through there.
Well that's pretty small, maybe 30 mils.
So you're pushing against it and the pressure's on the backside
it's not just immediately going to atmospheric on the backside,
and people were destroying injectors doing it.
So now they put, if you get one from us setup to do injections
like we're talking about, it has an injector here it has two
capillaries or a capillary that comes from this, goes up into a
valve, on the backside of that valve is a 7.5 psi pressure
relief valve so that if you do put too much pressure it pushes
it out the back.
See you keep a little bit of pressure on it and then it had
two tiny capillaries that come down here and to the injectors.
Generally with a syringe injection, you can or you
cannot, depending on which way you want to
work it, use the pump.
Some people like to, some people don't.
Some people like to as a timer more than anything else and they
know that it's pulling a sample through with
a little bit of pressure.
>> male speaker: [unclear dialogue]
>> male speaker: They said it's not available
but I thought they were going to put
it together for you.
I thought so.
I don't know, maybe I'm wrong,
maybe I'm thinking of someone else.
>> male speaker: Maybe someone different.
>> male speaker: Let me check with
Chuck about that.
Because that takes somebody coming up and putting it on for
you and more and more, what people are doing more and more
bioreactor fermentation work trying to find renewable energy
sources, so we're seeing this more and more where they're
really limited in the amount of things they inject so they want
to put a small injector on and they want to
have both capabilities.
We aught to make a part number out of it, but it doesn't exist
as a part number unless you order it from the factory built
that way, because they don't think you should do it, they
don't think I should do it, but I've done more than one.
>> male speaker: That's what we had
[unclear dialogue].
>> male speaker: The best way to illustrate
what will happen will be actually a two-way valve.
So you'll have a tiny capillary coming up the front, that tiny
capillary will come up to a valve, and it could either be
this way or this way.
On the back side we'll have that pressure release.
And then it will come out of this same fitting, down here, in
this case there's a dual fitting here so maybe it's a little too
small, it'll come back out of this and then into those two
splitters that go to the two columns.
But it'll also have a line that comes in here that
your simple line in on the back.
So if you switch it, you have the ability to switch and make
an injection from the back that then comes through these
capillaries or to close it and then go this way
or go through this capillary.
This option is somewhere around $4000, I think.
If you already own a new one.
So we're trying to get them to put together these parts so we
can do it economically, we've had it happen more than once,
people that get it and assume they can do that,
and it's not so.
And in fact on more than one occasion I think that they were
told that they could do it by somebody that didn't know what
they were talking about.
We're trying to fix the one we can.
>> male speaker: Any questions?
>> male speaker: I appreciate your interest,
if there's anything else I need to answer please let me know.
[no dialogue]