Drug Identification & Chemical Testing for DWI Defense
Blanks between Samples
Kevin Leckerman: I was talking about how to eliminate carryover and how to make sure there’s no contamination. The labs should run a blank between each unknown. So Defendant A’s blood gets tested, and then you put a blank between Defendant A’s blood sample and Defendant B’s. A blank is deionized water, so there should be nothing that comes out. If there’s carryover, then what you’ll see on this blank is maybe ethanol. Then you’ll know that there’s carryover and the testing process is compromised. If you don’t do that, you can’t prove that there’s no carryover, but laboratories won’t do that because it’s an extra expense and it’s extra time to create the blanks and put them into the computer.
So it goes in through the column and goes out through the detector. There is the flame ionization tip – you see how small it is compared to this quarter? Each substance that comes off gets burned up. The amount of molecules that comes out determines the quantity. With mass spectrometry, there’s a different method that’s being used.
If there’s one thing I want everybody to take from this it’s this: when you’re talking about gas chromatography, the machine is the gas chromatograph. The printout that you look at that shows the actual analysis is called a gas chromatogram. Don’t confuse the two, because if you go to court and start asking the chemist about the gas chromatograph that she looked at, the chemist if going to know you don’t know what you’re talking about if you don’t have the simple terminology down.
Gas Chromatography Errors
Kevin Leckerman: If you look for gas chromatography errors, there’s something called fronting, elevated baseline drift, and co-elution.
So these peaks come out, and on the chromatogram they come out like this. A good peak is when there is good separation between the peaks, they’re tall and skinny, and that’s what they look like; you can tell the difference between each compound. If there’s a problem with the gas chromatogram, there’s going to be a tail at the end of it or maybe a front to it. There could be split peaks; that means there’s not adequate separation. You can’t tell if this is actually ethanol. You may be able to tell that part of it’s ethanol, but you don’t know how much of it because you can’t quantify it. If it’s all mixing together in this one area, the machine is going to give you one result with all of this area, that’s no good. Shouldering is kind of the same thing as that. Broad peaks are when it’s not tall and skinny anymore. Broader peaks mean there’s a problem with the maintenance of the machine.
The column may get tired and need to be snipped, because the ends may get contaminated with all of these tests going through. There could be problems with the pressure, with the temperature – of this could be a problem and that’s why you see bad peaks, especially broad peaks if it’s a temperature issue.
Again, GC needs constants, not variables. Everything needs to be constant all of the time.
Presence of Drugs in Urine & Blood: Gas Chromatography/Mass Spectrometry
Kevin Leckerman: I’m going to quickly go through this.
It’s called the gold standard in testing. If you’re a defense attorney you really shouldn’t acknowledge it as the gold standard because there can be problems. Just because it’s being used doesn’t mean that it’s absolutely reliable. It allows for qualitative – meaning finding out what the compound is – and quantitative analysis. If blood and urine testing is being done, then it’s going to create dirty substances and that means it has to be cleaned often. That’s something you want to look at. How often are these machines being cleaned? If it’s not clean, again, there can be carryover contamination.
Here’s the mass spectrometer. It’s a little different from the flame ionization detector. The way it goes is the sample is injected. It still goes through the gas chromatograph, so gas chromatography is still used and the separation still occurs here. It just goes through a different detector. What this detector does is it blasts it apart – it takes this compound and smashes it into pieces.
So here’s the separation. You see here we’ve got cocaine. These numbers here are different molecules to create a certain compound. Every compound has different ions in it, essentially – different molecules – that are used to identify the compound. It has to have, let’s say, for cocaine: there have to be some ions at 185 and 105 and 85 and 65. That’s how you identify this. You blast it apart, and then you look at the pieces and try to figure out what it is. So the mass spectrometer blasts it apart, and then what you use is a library of spectra – essentially, these. These are supposed to be NIST-traceable, too. It’s a chart and you compare the two and you see if they look similar, and the library is used to reassemble.
So picture it this way. You take a bike, I attach a bomb to the bike, and I blow up that bike. Then you bring in another person and say, “Tell me what this is. You see all these parts here; can you tell me what it is?” You see two wheels, you see a seat, you see a bit of a frame, you see some spokes, and your educated guess is it’s probably a bike. That’s the process that’s being used here. They use the library to compare the two and come up with the idea that, “Yeah, this is probably cocaine.” But it’s not definite; it’s still up to the interpretation of the chemist to look at the spectrum, compare it to what your unknown is, and come up with an idea. “There are enough ions – or parts – to make this look like cocaine.”
For DWIs, as a defense attorney, it’s fantastic. It’s fantastic because they don’t quantitate. Why is that a problem? Well, they do the gas chromatography so they’re able to tell if there’s cocaine or marijuana in the person’s system, but they don’t bother setting up the machine to detect how much of the drug is in this person’s system. This could be a problem.
There’s something called limit of detection (LOD) versus limit of quantitation (LOQ). Limit of detection is easier for a laboratory. All they have to say is, “Okay, that looks like marijuana.” There’s a lower standard for what they have to find to be able to say, “We’re identifying this as marijuana.” With quantitation, you’ve got to have more ions. There’s a different and more complicated process which means the lab has to do more work, essentially. And if the lab doesn’t have to do it, they’re not going to do it. In a state lab, you’re dealing with people who are underpaid and overworked, and they want to get through their day as quickly as possible with the hundreds and thousands of different samples that they have to test.
Urine & Marijuana
Kevin Leckerman: Let’s talk about marijuana for a second. Marijuana in urine – usually the lab is not even going to test for the active component in marijuana, THC. They’re not looking for what’s called an active metabolite. (What happens is, when marijuana goes into your system, your system metabolizes it and breaks it down in a different parts. There’s going to be an active component of THC and there’s going to be a metabolite. Metabolite is inactive, so there’s 9-Carboxy-THC or THC-Carboxy. It’s not psychoactive; it doesn’t do anything to you. I could have tons of this substance in my system, but it doesn’t make me high at all. The only thing that it will do is that it shows that I used marijuana at some point recently. There’s a woman, Marilyn Huestis, who actually did a lot of testing on marijuana and found that up to seven days after heavy cannabis users abstain from smoking, they still found active THC in their system seven days later, and metabolites there as well. So what does it mean if you’re doing this GC/MS and you find this THC metabolite? It really doesn’t mean much. Can the chemist come in and say, “This person was using and under the influence at the time of driving”? Absolutely not. Again, it has no psychoactive effect. All it does is it reports past history.
Kevin Leckerman: When you’re looking at laboratories, keep in mind the following: there is no set standard for forensic laboratories. The EPA sets standards for environmental laboratories – what each environmental laboratory has to do to test water or whatnot. FDA for pharmaceuticals: there is a standard that every FDA lab has to abide by. But there isn’t a standard for forensic laboratories. They’re supposed to follow the International Organization for Standardization ISO 17025, but not all laboratories do that. You want to find that out. What protocols and standards are you following? Are you following the best standards? Most do not.
Challenge the scientists; challenge the laboratories. If you go through the articles that are out there, scientists will make up results. Not all scientists, of course. There are good scientists out there. But there are laboratories that have been found in the United States – state labs, city labs, county labs – to be guilty of misconduct, bad testing, and lying. You also want to know a little bit about the technician. Do a criminal history check to see if the person does have a record. Look at their CV, their training, their schooling degrees, so you can see if that person actually did graduate with a science degree from whatever university. Sometimes they don’t.
Finally, sometimes the technicians are only testing the blood; that’s all they’re doing. They’re putting the blood into the machine, they’re testing it, and they get a result. They’re not qualified to give an opinion on whether the driver was actually impaired or not. That’s not their job, and they may not be trained to do so. That’s more of a pharmacologist or a toxicologist’s job to do that. If it’s just a simple chemist who’s running the machine, make sure they don’t run their opinion if they’re not qualified.
At this point I’m going to hand it over to Chris for his part of the presentation.
Student: When you ask for the chromatogram in discovery, do you actually get a printout of all of their peaks and stuff like that, or do you just get the results and from there you can ask?
Kevin Leckerman: No, no, you get the chromatogram. There’s actual case law that says you’re entitled at least to the chromatograms, but you’re going to ask for the chromatograms for the calibration, for the internal standard that’s used (I didn’t get a chance to talk about that), you’re going to ask for the unknown – the defendant’s sample – you want the verifier, the control test; you want chromatograms for everything to show that they did it.
Student: Because then you can just look at it and eyeball whether there was any type of issue with the calibration or anything with the peaks or anything…
Kevin Leckerman: You got it. At least you understood what I was saying.