Lecture on Analytical Chemistry in BAC testing Part 10

The above is Part Ten from a lecture given by Attorney Justin J. McShane before the North Carolina Advocates for Justice “Advanced DWI Seminar”. This seminar happened on February 26, 2010. It was organized and hosted by John K. Fanney, Esquire of Fanney & Jackson, P.C. The following is a transcript of this video:

I spent some time doing science. Now I am going to give you the payoff here so you can understand it. The most important thing to understand with a chromatogram is that what we want are tall skinny peaks.  Not only tall skinny peaks but we want them to be symmetrical meaning that if you were to divide it in half the A portion is roughly equivalent to the B portion. So the only thing you need to know and the only thing you need to have a jury understand is that if it is not a tall symmetrical peak with sufficient resolution meaning the difference between peaks, it’s wrong. Who can’t remember that.  Tall, skinny, symmetrical, difference between peaks. So it’s the area, the area, the area, that’s why you want tall, skinny peaks that are sufficiently separated, if you don’t there is a problem.

Here is a particular type of problem. It’s called fronting or shouldering. What ends up happening is that it went through the column, and then it got stuck along its way instead. Let’s think about this for a second, if it was a tall, skinny peak it would be like that, the area is greater.  If the area is greater the result is going to be greater. They are going to over report your client’s BAC. Does everyone see that? If it is not a tall skinny peak, instead it is fat and ugly, of course there is going to be more area under the peak and they are going to say that the blood alcohol is greater. Another example is what’s called a baseline drift. Instead of it going straight across, it arcs up, there are reasons for it but that is beyond our need.

If it isn’t corrected like this one, again what ends up happening is the computer may sit there and give you that extra part that’s right there and say oh my God there’s more area, more BAC. You get tall, skinny symmetrical peaks that are of sufficient resolution or different from one another. You can get something that’s called peak tailing.  Again you want tall, skinny peaks but in this particular case you have another analyte that isn’t separated like those two that’s hitting at the end. That’s another analyte that’s there. If you had better chemistry you would be able to separate it out, but what ends up happening is it looks like a peak tail, not only is your guy getting screwed because of that, but it’s also adding in stuff that should not be there. What you are looking for is tall, skinny peaks that are different like that. That is what you want, anything short of that, no good.

Let’s move right along.

[Music: Jerry McGuire]

I show you that clip because the next time you go to court and you have a GC case, you are going to yell at your state expert and you are going to say not show me the money, you are going to say that to your client, but what you are going to do is say show me the separation. Show me the separation because if you remember that at the end of the process it’s chromatography, taking a complex mixture of stuff and separating it out so you don’t have things that are like grouped together. Separation, if you cannot show me Mr. Analyst your separation of like molecules, your junk, that’s all you have. If you haven’t challenged a GC case inside your county or inside your municipality whatever it is, start with something simple.

Show me the separation and this is what it should look like and the reason why is because all of these things are chemically almost similar.  There is only an extra carbon-hydrogen bond that is there between methanol, ethanol and then it becomes isopropanol and butanol.  And you have other things that just have a CL, an additional chloride that’s there. All these things that are chemically close to one another. If they can’t show you something that looks like this, where what they do is sit there and they say, “Okay, we have methanol, acetaldehyde, ethanol, those are those first three peaks that…”  They’re tall skinny peaks, sufficiently separated from one another – don’t come into court.

Mr. Analyst, show me the separation. If you can’t show me the separation, I don’t know, the judge doesn’t know, the jury can’t know that you can resolve these like things close to one another. Using information that we had before and moving right along as quickly as we can because we only have a little bit of time, this is what I suggest should be tested, this is a control run from an actual case that we had. Do you see elevated base line error that is there? Do you also see peaks that are not sufficiently resolved? Do you see issues that go along with that? That’s after I told him, I said I want to see the separation. I warned this guy, I dared him, I said “Bring it in, let’s go see it.” Brought it in front of the jury, showed them that and they said “Oh my God.”  Show me the separaton assay, low hanging fruit that you can do immediately even without an expert.

GCMS, GCMS is how to analyze solid drug doses with your drug cases. GCFID or Flame-Ionization Detector is basically what is going to be used for ethanol. Whether or not someone has cocaine inside their system they should be using GCMS. Same principals, you have a loop which is otherwise known as a column.  Then you have a Detector, it’s called a mass spectrometer. The process is not different. It’s just different code names, at the end instead of getting a chromatogram, and you get a Total Ion Chromatogram. This is what happens, after molecules separated out from its other neighbors and stuff like that, it comes through, after it has gone through the loop here that separates the things out for absorption it comes and it gets blasted, ionized, zapped into smaller fragments. That’s the way it works.

If you have a more complicated molecule you can come in there, it too gets zapped into its smaller parts too. It is the way to tell maybe uniquely whether or not an analyte of interest, cocaine is in fact cocaine. It results because it gets blasted apart, the end result and this is the mass fragments as it’s called, the little pieces that are there. It get’s transformed into a graphical representation that’s called the abundances. This is what it should look like at the end of the day. This is from and unknown, this is what it looks like and that is based upon.  Again taking a look directly at the mass separation. What they do is they take a known standard, meaning in this case cocaine that they got from a source that is pretty much indisputable and they say this is what it should look like to tell whether or not it’s cocaine.

It’s Sesame Street. One of these things is not like the other, one of these things. This came from an actual case where they are trying to say coca-juana was in our clients blood. You have to get the actual information to take a look at this. It doesn’t take a PHD to see what is wrong with this particular situation. 13/13, 31/31, 42 looks different, there is 42 and 43, this is our standard meaning our known showing only 55 up here on the unknown we have 54, 56, 72, 72 101. You can show that it is not what we expect to come from a traceable source. Is it coca-juana? Well I don’t know but they have to know.  The government has to know. They have to prove it to you. It is Sesame Street. We all remember Sesame Street. One of these things is not like the other, one of these. You just show to the jury, “Okay.”  It’s low hanging fruit.

2 Responses to “Lecture on Analytical Chemistry in BAC testing Part 10”

Leave a Reply

Your email address will not be published. Required fields are marked *