Episode 62: Dr. Bruce McCord on the Chemistry behind Crime Scene Investigations

Introduction

0:00Hi, you're listening to Let's Talk Chemistry, a podcast by Chemtalk. On today's episode, we interview Dr. Bruce McCord, professor of analytical and forensic chemistry at Florida International University. Dr. McCord highlights his research in DNA analysis, explosive detection, and drug analysis. His work has helped strengthen methods used by investigators and forensic labs to identify

0:32DNA and detect illegal drugs in real criminal cases. We hope you enjoy.

0:41Hello, everyone, and welcome back to another episode of Let's Talk Chemistry. I'm Mehreen, one of your co-hosts today. And I'm Amber. Today's episode is all about our special guest, Dr. Bruce McCord, a professor of analytical and forensic chemistry at Florida International University. Dr. McCord was an undergraduate at the College of William & Mary and completed his PhD at the University of Wisconsin in Madison. But before ending up in academia, Dr. McCord had a very surprising career path, including living in the Bahamas and working for the FBI.

1:13Also, like many of us, Dr. McCord had a different vision for his field of study starting out in college.

Dr McCord's Background

1:19Let's let our guest explain. My father was a chemical engineer, and I loved science. And I thought that I would, and I loved watching TV shows about nature. So I thought at the time that I would get involved in marine science and marine chemistry program. And William & Mary had a program called the Virginia Institute of Marine Science at the time. And so I applied there.

1:52When I got there, I realized that the Marine Science Center was pretty far away, and I really would have needed a car. And so instead, I attended, and I started to really enjoy the chemistry lab. And so I became involved in that. From there, I applied to a number of graduate schools, and Wisconsin was the one that I liked the most. I loved water sports, and Madison, Wisconsin was on this big, beautiful lake. And the funny thing is that when I got there to interview, the lake was completely frozen.

2:26So I walked out across the lake, I lay flat on my back, and looked all around, and you could see the university, you could see the capital. If you've never done it, it's an amazing thing. You can just lay down and ride on the ice, and you can see from us. As Dr. McCord highlights here, sometimes your career decisions aren't just influenced by academics, but also by your own interests. You might choose a university or workplace because of factors most people might not consider, like the fact that it sits on a beautiful lake. Yes, and it's always important to keep a good balance between work and your personal

2:58life. Although it seems like you might be sacrificing something, sometimes it actually opens up more opportunities than you think. For Dr. McCord, his interests and preferences led him to search for a job in a warmer climate. I started looking for places to work, and I had thought a little bit about doing a postdoc, but I really, my father had worked in industry, so I decided that I would look for an industrial job. It was very cold in Wisconsin, so I really looked in the southeast of the U.S., and I

3:32had interviewed at a couple of places. One was Dow Chemical in Freeport, Texas, and the other was Siba Geige in Mobile, Alabama. And I ended up going to Mobile, where I could continue doing things like my water sports love. I loved sailing and windsurfing, and we lived very, you know, near the beach. It was wonderful.

3:54When I got to, though, at Siba Geige, I wasn't doing as much research as I really wanted to, and so I thought, well, maybe I should look for a government job. And the only government job I found was the FBI. And so I applied there, and at the same time, I also applied for a job in the Bahamas, because I thought, well, maybe I'll get a plant trip, and I can have a little vacation with me and my wife before we get the job at the FBI. Turned out, I didn't hear from the FBI right away, but I did hear from this company, Syntex

4:27Pharmaceuticals, in the Bahamas. And so I lived in the Bahamas as a chemist for a year. I had a condominium on the beach, and we had a sailboat tied up at the beach, and we would have friends over every Saturday night, and we would go out and spear lobsters and then bring them back and cook them. Wow. Working in the Bahamas sounds like so much fun, and it's such an unexpected place to consider when looking for a job. Although Dr. McCord enjoyed his time in the Bahamas, it had to come to an end, because

4:57a new opportunity had presented itself. For about three months into that, the FBI calls and says that we're still interested in the job, and I had to say yes. Although, I really didn't want to leave the Bahamas. And so, we moved to Washington, D.C. My wife got a job with the U.S. Patent Office, and I worked for the FBI Laboratory in Quantica. While I was there, I had gotten experience when I was working in the industry on a lot of issues with robotics and automated instrumentation. And the FBI had a project to develop DNA typing.

5:32And they gave me this side project.

DNA Analysis Research

5:35I had been working on counterterrorism and explosive residue dissection and developing a method called capillary electrophoresis. And one day, one of my bosses came by and said, can you do DNA with that thing? Because everyone thought at the time that electrophoresis was usually for large molecules, and I had been using it for little explosives. And the thing was, well, sure, we'll give it a shot. And at that time, people had been developing what are called entangled matrices for large

6:05molecule separations with capillary electrophoresis. And the idea was that instead of using gels, you could use dissolved polymers, something like syrups. And the advantage of that was that if we could develop a way to run the forensic DNA, which is highly repetitive, and basically the difference between, say, you and me would be if we looked at a particular locus, you might have four base repeats in your DNA. They're called microsatellites or short tandem repeats.

6:36And I might have five, or we could have the same number. And it's totally used for identification. It had been run by gels, and so I was looking at developing a way to do it by capillary electrophoresis. And it did work. And ultimately, the FBI switched to developing short tandem repeat analysis by capillary electrophoresis. And now it's pretty much used worldwide. And so we had some of the first papers on that kind of application. And that was one of the things I did at the FBI.

7:07Wow. It's amazing to hear that Dr. McCord's research is now being used worldwide in forensics. The best feeling as a scientist is being able to see your own work applied in the real world. I definitely agree. Working in forensics is such an interesting application of chemistry, as well as other areas of science. I am curious, though. Why did Dr. McCord decide to leave the FBI to work in academics? I think our scientists can answer that one for us. It wasn't particularly stressful. It was just that there was a time where I wanted to do...

7:41I have these ideas, as you can tell. And I had projects in drug analysis. I had projects in explosives detection. I had a lot of projects in DNA analysis. And at one point, the DNA analysis project became so important that I was almost being forced to drop the other research that I wanted to do. And I realized that it was time for me to go out on my own. And I tell people that are looking to be professors in schools and universities, you reach this point where you know what you want to do, and you're driven, and you just don't want anything to get in your way.

8:22And so that was the time. And I think having the... It's a wonderful experience. It's very hard to get training in how to mentor graduate students and how to develop a research program. And the FBI laboratory was one of the best places in the world to do that. And I think it was really successful. And I think they would agree that it was a wonderful thing for me to be there. And also, I continued to work with the FBI after I left. So it was just a wonderful situation.

8:53I had this dream. I knew that at some point, I wanted to become a professor in an academic situation. And all of that work that I did there led me to it. And I'm eternally grateful to them. Even though Dr. McCord stopped working at the FBI, his research was still heavily focused on applications of chemistry at crime scenes. Dr. McCord worked on several categories of projects. One example is analyzing degraded DNA, which was useful for identifying victims of mass disasters. Another was detecting what type of DNA was found at each crime scene, as in where it came from in the body.

9:31Another was analyzing explosive materials down to the ions that they are composed of, in order to develop new methods of detection. One method his team developed was capillary electrophoresis on microchips, which could be applied to the explosives, but also to DNA. This led to some exciting developments in DNA amplification. But we'll let Dr. McCord explain further. One of the things that we did with the DNA was that we realized that with these little chips, we could... And we weren't the first to do this, but we were looking at, you know, the forensic application and looking at how fast we could go.

10:06And we realized that with these little chips, we could get a DNA separation in 80 seconds, which normally took about 40 minutes. So going from 40 minutes to 80 seconds, we began thinking, well, maybe you could even use these things in airports or something, where you really needed a rapid analysis. But the problem was that our little chips could do the analysis in 80 seconds, but the PCR took, oh, 45 minutes to an hour and a half to amplify the DNA so we could run them on the chips. So we started playing around looking at really high-speed enzymes and high-speed PCR.

10:43And ultimately, over the years, we were able to bring the time that it took from less, you know, roughly 90 minutes or so down to about seven minutes. And so we realized that we had this little chip and we had this seven-minute amplification and we could do the whole thing in under 15 minutes. Science can be really fun, but also annoying at times, when some of these processes take so long to complete. Normal DNA amplifications takes way too long to conduct in a real-life setting, so shortening that time will really help us develop ways to use it at a crime scene.

11:18Yep. It's really exciting that people like Dr. McCord are making science so much more convenient and applicable.

Drug Detection Methods

11:24In the McCord lab, they are also investigating strategies to detect different drugs at very low levels. Just like we heard with DNA, drug detection is readily linked to various crimes and also has several legal implications. Dr. McCord can tell us about some of the analytical chemistry techniques used in identifying these drugs. One of the problems that we were involved in very early on in Ohio University and other places was the problem of drug-facilitated sexual assault.

11:55And what that means is that you could be at a bar and someone might slip something into your drink and then you'd get amnesia. You wouldn't know where you were and someone might steal something from you. They might abuse you, assault you. And we were trying to figure out if there were ways that we could do this. And we came up with a process where you basically would put a fluorescent tag on the drug and then you could detect it at very low levels. But we realized that this only worked for certain kinds of drugs that were amenable to change.

12:30And so we switched to using a really bizarre technique called surface-enhanced Raman spectroscopy. I only call it bizarre because it's really interesting. And the basic idea is that if you shine a laser onto the surface of a sample, most of the laser reflects off the sample and comes back at the exact same way that you start with. But a small, very small proportion of the light that comes back is reflected and interacts with the molecule itself.

13:04And this process, which is called surface-enhanced Raman spectroscopy, works really well if you have nanoparticles or a really roughened gold surface. So if there are metal particles involved, they can develop what are called surface plasma resonances. And these interact with the laser light coming into the surface and molecules that might be attached to the nanoparticles. It gives you like seven orders of magnitude of intensity enhancement, which gets to the point where you can always detect small molecules.

13:35And so we realized that if we use that technique, not only could we detect drugs at an extremely low level, we could also speciate them because this is called inelastic scattering. This interaction with nanoparticles, the drugs, and the light create this inelastic scattering, which gives you the spectrum that you need and lets you identify the drugs. Surface-enhanced Raman spectroscopy, or SIRS, clearly has an advantage to very small quantities of a chemical of interest.

14:06All a chemist needs to do is use rough metal nanoparticles, I think gold is the standard, and adsorb, or attach, a particular molecule to the surface of the particle, like a drug of interest. Then, a certain light wavelength is shined down on the sample, and scattering can be observed. If a sample has a spectrum that resembles a known drug, it can be inferred that that drug may be present in a small amount. Some of the assault drugs that Dr. McCord mentioned have extremely low doses necessary to cause a biological reaction, so other methods didn't always work.

14:43As Dr. McCord will tell us next, the typical method that's used for detecting these drugs and others are immunoassays, which use antibodies to detect specific chemicals, like COVID tests. As we'll hear, this type of assay is slow, and, if you can believe it, too specific. Well, the problem right now in analysis, for example, of this drug fentanyl, which is killing 70,000 people last year, one of the big problems with fentanyl is that you could use an immunoassay that would be targeting one particular kind of fentanyl,

15:15but there's all kinds of drug analogs that notorious criminal elements use to try to get around the existing laws of the United States in terms of illicit drugs. So you can make a new kind of fentanyl that might not be scheduled, and then they could get away with selling it for a short period of time until it again pops up. And the problem with these analog drugs is that, first of all, they're putting them into pharmaceutical preparations or clandestine part of pharmaceutical plantations, and it's killing people.

15:48And the other thing is that it might not show up on your immunoassay. So what we wanted to find was a really generic method that would be the front end, something you could do very fast before you had to take it to the lab and do a real analysis. So we developed these methods with portable Raman spectrometers where we could detect the drugs at really low concentrations and wouldn't have to use those immunoassay strips. And everyone's familiar with how these immunoassay strips because that's what you use to detect COVID as well. So you could also detect drugs with these things.

16:20As I said, we wanted to develop something that was much more flexible and could switch from different kinds of drugs. So we have applied it to benzodiazepines, which were the original date-rate type drugs. We've also looked at cannabinoids, cathinones, and most recently, opiates and fentanyls. So that's the other project. So the two sides of my brain, the DNA separations and the analysis of drugs and explosives. I think it's amazing how this technique allows field investigators to do a mobile analysis to detect these drugs.

16:53When managing a large lab, I think it makes sense to have different projects moving forward at the same time. In a previous episode of ChemTalk podcast, Dr. Chalfi, who earned the Nobel Prize for the discovery of GFP, mentioned that by working on two things instead of one, there are always more opportunities for progress. Yes, absolutely. And what better way to enhance progress forward than by hearing the advice of Dr. McCord about reaching out of your area of expertise and learning about techniques and discoveries in other fields. We've heard it on this podcast time and again, collaboration is key.

17:25The focus is often to figure out ways that discoveries develop for other fields, like medicine or like physics or like chemistry. How could they be applied to problems in forensic science? And it's a whole different world because forensic science involves not just the chemistry, but also the interaction with the law. And you're trying to figure out ways to improve the detection of dangerous substances or DNA

18:01that would hold up in court, that could be used by laboratories. And in our case, we really want to develop things that also maybe could be taken to the field so we can actually help the investigators find the samples they want and not waste time looking for things that aren't there. And then there's a whole other wrinkle to it too, because for the method to get used, it has to be acceptable to court.

18:32It has to be something so much better than what people are currently using now. And so it's a complex problem, but it's something I've really enjoyed. Not only does Dr. McCord mention the overlap of scientific fields, but forensics also relies on collaboration with the law. When they're working on developing new techniques, they have to be a strong replacement for the existing technique. At the beginning of our chat with Dr. McCord, he talked about all the different hobbies he has outside of the lab,

19:03and I was excited to hear that he still does those activities. The key for Dr. McCord's work-life balance and being close with his family is doing things together. His wife is a physicist, and he has three daughters, two with chemistry PhDs, and one who is working on a degree in computer science. Let's hear what Dr. McCord and his family do outside of the lab. We were three nights a week in different jazz groups. On the weekends, I like to go sailing or windsurfing if there's wind. And I just try to revive the whole family in all of this.

19:35I think it's really important. And of course, my wife is involved as well. She is a physicist. And we just try to inspire. I try to inspire people. My children, my research students, my friends. We just, we all work together. It's kind of, you try to, I think in graduates training and at least in college and research,

20:05it really helps to have a lot of people involved. So I try to involve undergraduate students, sometimes high school students, master's students, PhD students, people that have already gotten their degree, people that are in laboratories nearby, like the local crime labs, like people in other universities. I have currently, I work also, we work in developing forensic side programs for high school teachers and high school kids.

20:35And we just put on programs and we try to support the science. And we did. And when I was at the FBI, I did workshops for crime labs. And they would come to the FBI and we would teach them various types of science, like chromatography or drug analysis or arson investigation, things like that. And we've just continued that. We do that at national meetings for people that are employed. We do that for people in school, you know, from, you know, eighth grade through 12th.

21:08And we do it for the students that we have now. It's just what we do. I think the music keeps you from, the music and the sports keeps your balance together and getting involved in just various community activities. I've always done that, you know. And for example, a really big thing for us was getting involved in the Girl Scouts, getting involved in women in science, getting involved in science programs for forensic science,

21:39STEM programs. We recently did a program on drug analysis at the local science museum. It was really fun. We got a group of people coming in from a, you know, from a couple Girl Scouts groups. And we taught drug analysis using color tests and micro, micro spot tests and things. It was really fun. So we do those kinds of things. And we do it for adults and we do it for all ages. I know I've heard it from other scientists and professionals on this podcast,

22:10but it is so, so, so important to keep your interests outside of your work. All of your hobbies and talents should be nurtured alongside your scientific endeavors. I think it's great how Dr. McCord and the places that he's worked at support bringing science to others. I mean, the Girl Scouts that have learned those forensic techniques might go on to study chemistry and forensics. I think it would be amazing to learn about forensic techniques from the FBI. I completely agree. In his closing remarks, Dr. McCord gives some advice to be a successful science student working on a project like this.

Advice for Science Students

22:42You have to be driven. You have to want... I typically get students from all over the world. Currently, I have a student from Turkey, another one from Thailand, many from the United States. I get students from South America, from the Caribbean. They come from everywhere. I mean, I think one of the things we're proud of is how multicultural our group has been over the years. And I think what brings them all together is a love of science and particularly a desire to work in the field of forensic science based on experiences they've had or things they've read.

23:24And the key to succeeding in that, though, is to have a really solid background in science and math. You can't replace that. And a lot of people think, oh, well, this is so much fun and so interesting. I want to do it. But you've got to have the solid background. So one of the things that, for example, that we do here at FIU is to get into our program, you have to have a bachelor's degree in science, chemistry or biology or engineering. I'm physics sometimes and sometimes other things.

23:55But it has to be a solid science background. And then at the end of the four years when you're here, you can either go on and get a master's degree or you can go into our certificate program where we send you out on internship, where you'll develop ways. You know, it's not enough to take classes. It's also, you know, have you interacted with police laboratories or police ride alongs? Have you done these kinds of things that show you really have a dedication to your field? And once you put all those things together, then you're the kind of student that we want to have.

24:26And it's a devotion and a dedication to the field. And also having the practical experience is so critical. You know, having some experience working in a laboratory with your hands, understanding how to develop a project, how to, you know, write the results down in a lab notebook and publish them. These are the critical things in our group. It gets so, so long. And I'm going to say, I think at this current time, I've graduated about 34 PhDs and about 16 master's students.

25:00We've also had loads of visiting scientists come from all over the world. You name the country, they probably come from there. And just, yeah, it's just what we do. It cannot be understated how important it is to try science research when you're looking at graduate school. I like how Dr. McCord's lab mentions the diverse group of scientists he works with and how that positively impacts the work done. I agree with the importance of students' drive and enthusiasm, as well as their skills like organization and communication.

25:34Those are definitely skills that all scientists work on daily. We very much appreciated having Dr. McCord on the ChemTalk podcast today. And thank you, everyone, for listening. Be sure to tune in next time. Bye.

25:50Thank you for listening to Let's Talk Chemistry, a podcast by ChemTalk. We hope you enjoyed it. For more information on today's episode and countless chemistry resources, please visit our website at www.chemistrytalk.org.