“Crack”-ing the Cocaine Case
Michaela Harper, chemistry ’12, may just have the best internship ever: She earns university credit and a small paycheck and has a guaranteed job when she graduates—and her work will put bad guys in jail. As a trainee in forensic chemistry for the Drug Enforcement Administration (DEA), Harper is learning to analyze illegal substances seized in drug busts.
Harper first started working for the DEA in 2009, intending the experience to be a one-time summer accounting job. By the next summer, she was working at the agency through the federal government’s Student Career Experience Program (SCEP), which, upon graduation and internship completion, can lead to a permanent job. Through SCEP, a student interns for at least 640 hours. To complete this requirement, Harper works 20-hour weeks during semesters and fulltime over the summer. And so this Medford, New Jersey, native has turned the obligatory summer-break job into the makings of an exciting career, no photocopying or coffee-fetching necessary.
Harper may be a trainee, but she does the same level of work as DEA chemists—testing real drug samples from pretend cases, until finished with training. Two big factors in sentencing a person accused of drug possession are the drug’s salt form and purity. She is almost finished with learning the protocols for powders and is about to start the much harder task of pill sampling. A pill must be crushed into a powder to perform testing, thus creating a challenge, because there must be enough material in the original form left over for evidence. If she crushes too many pills to perform the tests, there will not be any physical evidence of the original pill form to present in court. The work can be demanding, but Harper enjoys the feeling of accomplishment when she correctly analyzes evidence on her own, knowing that someday her results will be good enough for court testimony.
The first step to running tests on an unknown powder sample is to determine the drug involved, since proper analysis depends on its identity. O ne presumptive test often performed is a color-reactant assessment, for which a forensic chemist apportions small amounts of the sample. Scott’s reagent solution, a mixture of cobalt thiocyanate dissolved in water, is commonly added to the sample, followed by hydrochloric acid. A cocaine base turns pink from the cobalt solution, then blue turning to pink with the hydrochloric acid. When chloroform is added, a pink top layer and blue bottom layer indicate cocaine. Once the chemist has a better idea of which type of illicit drug is in the sample, further tests confirm its identity and purity.
One instrument often employed in drug analysis is the gas chromatography-mass spectroscopy detector, which combines two important tests into one machine. Gas chromatography separates the components of a powder sample by injecting it with an inert gas, like helium, that carries it through tubing coiled into a cylindrical column. Each type of molecule progresses around the column at different rates, depending on its affinity for the tubing’s walls and the material in the center of the column. Using these progression rates, the machine isolates the molecules and their prevalence within the substance. The mass spectrometry section then vaporizes the substance (i.e., transforms it into a gas) and ionizes the components, fragmenting them into smaller, charged particles with unique masses. An electric field exerts a force on a moving charge to change its speed, and a magnetic field applies a force altering the charge’s direction of motion. The magnitude of the electromagnetic forces depends on both a particle’s charge and mass: A highly charged particle experiences larger forces, and a massive particle resists changes in motion due to its high inertia. The charged fragments passing through the electric and magnetic fields of a mass spectrometer separate, depending on the magnitude of the forces they experience, allowing chemists to collect and measure identical components. The instrument produces a mass spectrum, which is a representation of the intensity of the charged components and the mass-to-charge ratio (m/z). The position and intensity of the m/z values are called a fragmentation pattern and provide qualitative information about the compound. The resulting fragmentation patterns of each component of the sample are unique, allowing for the confirmation of the identity and adulterants of any illicit drugs. Finally, the chemist compares her results to substances listed in references, like the Merck Index, a catch-all guide of chemical and physical properties of every known chemical compound.
Before she could even pick up a pipette at the DEA, Harper had to learn the agency’s strict policies for evidence handling and testing procedures. Like any other law enforcement agency, the DEA stresses the importance of proper handling of evidence, because any break in the evidence chain of custody can exclude the sample’s use as case evidence. Harper credits her organic chemistry lab classes for providing an introduction to calculating uncertainty on data results and for using laboratory equipment, but the DEA has more specific protocols and very complex machines requiring extra training. To qualify as an expert witness at trials, she must, not only analyze drug samples correctly, but also be able to explain technical, jargon-laced results to the average Joe in the jury.
“Orgo” was not the only AU class that helped Harper’s work efforts, others, including Criminalistics, Crime and Society, a General Education chemistry class, touched on her research. For a case-study assignment for this class, e.g., she created a realistic scenario, “following” the case from an undercover buy through the lab analysis and the trial to court sentencing: “It’s interesting to think about the whole process.” Professor James Girard, who taught the class and chairs the Chemistry Department, is Harper’s internship advisor. She keeps him updated of her progress at the DEA by sending him the monthly reports she does for work.
No other AU student had used SCEP to work with the DEA before, but with the help of the Career Center, the paperwork went through and now her internship credits fulfill a Chemistry Independent Study requirement— but the SCEP’s big challenge was earning the DEA’s top secret clearance. She has already decided to continue working for a federal agency, even once she completes the program and graduates, and hopes to remain in her current location for several years before moving to another laboratory. Harper also plans to attend graduate school for forensic chemistry— whenever her busy work schedule will allow.