The Chemistry of Cannabis: Detection of Cannabis Farms

*This blog post is purely for educational purposes. We do not support the production, distribution, or consumption of Cannabis.

Welcome back! So, since you’ve clearly been overwhelmed by the amazingness of the information in our blog posts, we think you deserve a refresher. In previous blog posts, we have discussed the effects thatCannabis has on the brain, and the different forms through which Cannabis can enter the body and results in these effects. In this blog post, we’ll discuss new and innovative ways that law enforcement is using to detect Cannabis farms.

Scratch ‘N Sniff™

(yes, you read that right)

A charity organization based in London, England has come up with an innovative way to help police officers locate Cannabis farms. The organization has created Scratch ‘N Sniff™ cards. These Scratch ‘N Sniff™ cards that mimic the scent of Cannabis in its growing stage, and are being distributed to English citizens so that they can to familiarize themselves with the smell of growing Cannabis and can notify the police if they detect the scent. So far, the organization has issued more than 200,000 scratch and sniff cards to hotspots in England, and, there has been a 28% increase in information from the public on Cannabis farms.

Now, how do these Scratch ‘N Sniff™ cards work? The ideas of chemistry can be applied to the Scratch ‘N Sniff™ technology through the ideas associated with entropy. Entropy is the number of ways a system can be arranged. In this case, aroma molecules that are microencapsulated are at a state of low entropy, since they are enclosed in minute capsules. The manufacturing process of scratch and sniff cards utilizes this entropy idea. The diagram shown below illustrates the process. In general, the process includes taking the aroma-generating chemical and encapsulating it in gelatin or plastic spheres that are a few microns in diameter, and this traps the odor. A certain chemical catalyst is used to bring about the reaction which finalizes the encapsulation of the odor. In other words, the catalyst is the metaphorical “kick in the pants,” or the thing that bring about the reaction. This  reaction requires a “kick in the pants” because it will not happen on its own; this type of reaction prevents particles from diffusing, as they would “like” to, and in order to get particles to do something they don’t want to, you have to bribe them with energy.

When these capsules are given another metaphorical “kick in the pants,” or an activation energy, they are released and they dissipate and spread the scent. Even though the particles want to diffuse, a “kick in the pants” is required to give them enough energy to break through the capsule. This energy required to get this reaction going comes in the form of kinetic energy from a person, when he/she scratches the card, applying friction to the capsules. The aroma molecules are then released, and since they have more volume to diffuse into, they achieve a higher state of entropy.

This idea of  Scratch ‘N Sniff™ technology, then, can support the notion that the entropy of the universe is always increasing. Spontaneous reactions, which have a negative free energy value, are constantly occurring in the universe. The Scratch ‘N Sniff™ system is one primary example of this chemical theory. Since this technology embodies the principles underlying entropy, then it also applies to The Second Law of Thermodynamics. This law states that “In an isolated system, natural processes are spontaneous when they lead to an increase in disorder, or entropy.”

Thermal Cameras

Authorities are beginning to use thermal cameras to detectCannabis farms. Often, Cannabis growers employ heat lamps when growing indoors. Further modifications to the growing area typically include the addition of ventilation and irrigation systems. Thermal cameras are being used to detect growers who hideCannabis around other plants, rendering them invisible to the naked eye. However, the grower must make some changes to the soil, which allow these cameras to detect hidden plants. The soil is turned over and the vegetation around the plant is trimmed off to allow for better absorption of water and nutrients. As a result the soil also absorbs heat at a higher rate than the other surrounding plants. Consequently, they stand out in thermal scans.

Just like any other camera you use, thermal cameras detect light. However, they differ from conventional cameras in that they detect different wavelengths of light. Thermal cameras detect infrared light as opposed to visible light. Because the lamps generate heat, the system emits infrared radiation. At the atomic level, the heat is simply the movement of particles. When the particles collide with each other, they can affect each other and induce a dipole oscillation. Due to this volatile distribution of charge, electric and magnetic waves are emitted as photons within a certain range of frequencies. Finally, the hotter an object is, the shorter the wavelength it emits. Thus, thermal cameras display hotter areas closer to white and darker areas closer to black. Also, if an object is hot enough it can emit thermal radiation that is visible to the human eye, a simple example being fire.

Well, that’s all folks!

Sherlocked: Unlocking the Chemical Mystery

We’ve all heard the story of Hansel and Gretel- kids abandoned in the woods encounter a delectable house made of candy, meet an evil witch in the candy house, and get captured and force- fed sweets by the said cannibalistic witch so that she can inevitably gobble up the children. Luckily, the protagonists in this classic fable survive when they push the witch into the very oven she was planning to cook them in, and it’s a happily ever after for everyone (except the witch).

In our case, though, there is no convenient oven to trap the witch in- or rather, the criminal mastermind. Indeed, we have chosen to analyze a scene from the modern- day British television crime drama, Sherlock. A contemporary adaptation of Sir Arthur Conan Doyle’s classic detective stories, the show integrates modern forensic techniques to showcase Sherlock’s incredible skills of deduction in a more realistic light. But what does this have anything to do with a classic German fairy tale?

In a scene from the episode, The Reichenbach Fall, we see Sherlock investigating a case of children gone missing- vanished from their beds. Although seemingly stumped at first, he soon realizes that one of the kidnapped children, having a predilection for spy books, was clever enough to leave behind a trail of linseed oil, which supposedly exhibits fluorescence under the presence of ultraviolet light. Sherlock then takes a scraping of the footprints the kidnapper left by stepping in the spilled oil and analyzes the traces left behind in the oil to determine his precise location. The examination leads him directly to a chocolate factory, where the children had been driven dangerously ill by eating copious amounts of candy and were on the verge of dying in the arson of the factory. Sound familiar?

The kidnapper is the “consulting criminal” Moriarty, a man who acts as a consultant to commit crimes for his clients. He is also Sherlock’s primary rival in the show and the antithesis of Sherlock’s “consulting detective” position. He is clearly establishing the Hansel and Gretel motif here intentionally, being that the kidnapped siblings were German, left behind by their parents over term break and taken to a place where they nearly meet their doom through burning. It’s undoubtedly a relief that the ingenuity of the child paired with Sherlock’s observance saved the victims, but the modernistic juxtaposition of the series makes us consider the unavoidable question: what if this hadn’t been just a plot event in a fictional series? What if it were real? Simply shining a special light over the crime scene to reveal the answer seems a tad too easy to be true. Does linseed oil indeed show itself under UV light? If so, can this behavior be explained chemically?

Figure 1. Structure of linseed oil, comprised of polyunsaturated fatty acids and ester bonds.

As it turns out, linseed oil is a triglyceride capable of fluorescence after degradation when exposed to UV light. Derived from the seeds of a flax plant, linseed oil is fatty oil that contains polyunsaturated fatty acids. It is commonly called a drying oil, because when exposed to oxygen in the air, it undergoes a process known as polymerization, or drying. This is partly due to its composition – it contains an unusually high amount of alpha-linolenic acid as well as di- and triunsaturated esters, which makes linseed oil inclined to polymerize when brought into contact with atmospheric oxygen. This autoxidation, the exothermic addition of oxygen to an organic compound, causes subsequent crosslinking and the curing of oils. An atmospheric oxygen molecule in the air immediately pounces on the long hydrocarbon chains of the oil’s fatty acids, inserting itself into carbon- hydrogen bonds adjacent to one of the double bonds within the unsaturated fatty acid. This causes a domino effect in which a number of addition reactions, organic reactions in which two or more molecules combine to form a larger one, occurs in rapid succession. This in turn forms hydroperoxides that are susceptible to crosslinking reactions. A vast polymer network forms as a result of the bonds between neighboring fatty acid chains, and is visible as a skin-like film formation on samples. The polymer network may undergo further change over time; it can transition from a system held together by nonpolar covalent bonds to one governed by ionic forces between the functional groups as well as the metal ions present in the paint pigment. This change is primarily due to the functional groups in the network becoming ionized. Moreover, the eventual polymerization process results in rigid, somewhat elastic films that do not readily flow or deform. The early stages of polymerization can be monitored by changes in weight; linseed oil in particular increases in weight by 17 percent as the reaction occurs. With regard to linseed oil, its structure becomes a huge, chain-like polymer network of molecules, as shown below in Figure 2. As a result of this process, free radicals are produced. Free radicals are substances containing an unpaired electron, which makes it highly reactive. More addition reactions ensue, each step producing additional free radicals. They continue to engage in polymerization until all the free radicals have collided and  their unpaired reactions have been combined to form a new bond, at which point the reaction halts. The polymerisation stage occurs over a period of days to weeks, rendering the film dry to the touch.

Figure 2. Linseed oil undergoes polymerization to form a huge, chain-like polymer network of molecules.

 Fluorescence is generally characterized by the presence of aromatic compounds and their delocalized electrons. In organic chemistry, aromaticity is a property of conjugated cycloalkenes whose p-orbital electrons are delocalized and provide a framework for a stable and planar molecule. Typically, fluorescent compounds will be highly conjugated. In addition, it is well established that these fluoresce when exposed to ultraviolet light as shown in Sherlock.  When a vegetable oil, such as linseed oil, is heated, its fluorescence is initially diminished and indiscernible due to the decomposition products and nitromethane, but as the oil progressively becomes polymerized, its fluorescence increases in intensity. In the episode The Reichenbach Fall, Sherlock did not heat the linseed oil, but instead the oil simply revealed itself under the presence of UV light.

Figure 3. When electrons of a substance absorb energy gained from UV light, they are excited to higher energy levels and then fall back to their ground states, emitting energy in the form of light. Fluorescence is light emitted that is in the visible spectrum.

In order to be fluorescent, a molecule must be highly absorbing, and possess the appropriate structure andelectronic energy levels. Fluorescence occurs when electrons absorb energy from the UV light to become excited to a higher energy level. When these electrons come back to the ground state, energy is emitted in a form of a light. Because the light that is emitted usually has a longer wavelength than the energy absorbed, we are able to see the light emitted as fluorescence. This is due to something known as the Stokes’ Shift in which a molecule that absorbed light is now in the excited state releases a bit of the initial energy first before releasing the rest of the energy in the form of a weaker proton to get back to the ground state. Linseed oil is able to exhibit fluorescence because of both the chemical and physical properties that it has. As stated before, linseed oil contains many fatty acids. Some of these fatty acids contain pi bonds which are very good at absorbing and emitting light. This is due to the fact that the energy separation for an isolated pi bond is very large, and so the ultraviolet light with its large energy and short wavelength can excite the electrons in the pi bond.  However, linseed oil does not fluoresce brightly because linseed oil does not contain conjugated pi systems (a system in which double bonds alternate with single bonds).

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Figure 4. The Stokes’ Shift occurs when an excited molecule releases some of the initial energy before releasing the remainder of the energy in form of a weaker proton to return to the ground state. This allows us to view the light emitted as fluorescence.

We thought this investigation seemed a tad too easy  to be 100% chemically accurate, and we were correct- partially, at least. As discussed above, linseed oil does in fact dry into a somewhat elastic film through a process termed polymerization- however, the entire affair can range time- wise from several days to weeks, indicating that by the time Sherlock and Watson had arrived at the scene, the state of the oil most likely would not have sufficed for UV testing. Moreover, linseed oil’s fluorescent properties are significantly less notable than that of conjugated pi system- containing compounds, the light emitted being of longer wavelength and weaker energy than that absorbed. And now for the final kicker- dried linseed oil barely exhibits any fluorescence under UV light than it does as a viscous liquid. The non conjugated system in the oil compound has its double bonds broken when dried, thus notably lessening the already minimal degree to which the substance fluoresces; no question that it certainly would not have glowed with the same quality of brilliant luminescence as it did in the scene. Nonetheless, we applaud the Sherlock forensics team, whoever they are, on their ingenuity on thinking to use a drying oil as a means of tracing a kidnapping to parallel the trail found in Hansel and Gretel. Though it might not have worked in reality, we also know that  bending the truth is sometimes necessary on the screen- and this definitely receives full marks for originality!

Unlocking the Chemistry of Crime: Serotonin

This video featuring Adrian Raine provides the perfect introduction to the connection between neuroscience and crime.  The exact scene can be found here.

 Crime.

It exists everywhere; in every city, in every country, every day of the year. In movies like Minority Report, the government has  implemented programs to catch murderers before they act. But in the real world, criminals pounce on their prey daily. When one thinks of crime, evil and devious convicts come to mind. But what if crime can be entirely explained through science? Can what urges a single person to perform an act so disastrous, so devious, so illegal, be revealed through science?

Crime & The Human Brain

This image of the human brain displays the different sections different sections.  The red section is the frontal lobe, the green section is the temporal lobe, the yellow is the occipital lobe, the purple section is the insular cortex, the black section is the brain stem, and the blue section is the cerebellum.

In a recent study, brain scans were administered to individuals with an antisocial personality disorder (a common characteristic of many criminals). This disorder typically causes one to “have no regard for right and wrong…[and] violate the law and the rights of others,” according to the Mayo Clinic, a non-profit medical research organization. The brain scans of those with the disorder were compared to a control group without mental disorders. The results concluded that those suffering from the disorder had an 18% reduction in size of their brain’s middle frontal gyrus and a 9% reduction in the size of the orbital frontal gyrus. Both of these sections are important parts of the brain’s frontal lobe.

 

This diagram outlines the different sections of the brain.  The frontal gyrus, which was examined in the study above, is highlighted in orange. Braunstein was a convicted sex offender. One can see the smaller frontal lobe, which is also not as activated in Braunstein as in the normal brain. The frontal lobe controls decision making, problem solving, control of purposeful behaviors, consciousness, and emotions.  The frontal lobe is part of the cerebral system which deals with goal related behavior, distinguishing between “good” and “bad” and resulting impulsive decisions.

Another study examining psychopaths versus a control group demonstrated that psychopaths have a thinner outer layer of the cortex in the amygdala and an 18% smaller size of the brain in that region. Adrian Raine, chair of the Department of Criminology reported that the amygdala is the part of the brain responsible for emotion; thus, psychopaths experience inhibited emotional responses.

Beyond psychopaths, convicted criminals tend to demonstrate behavioral differences compared to the average civilian. Raine explained, “There is a neuroscience basis in part to the cause of crime.” Many of the signs indicating one as a criminal can be found in the brain early on, before an individual develops into their psychopathic or criminal tendencies. A study conducted by Nathalie Fontaine found that those who tended to be callous and unemotional as children had a higher risk of becoming psychopaths in adulthood.

But what is it exactly that makes one predisposed to these criminal tendencies?

What is the difference in the chemical makeup of the brain of a criminal?

How does this all tie back into chemistry?

What is Serotonin?

Neurotransmitters are chemicals in the brain that are responsible for sending signals to different cells throughout the nervous system. Serotonin is one of the most abundant transmitters in the dorsal raphe section, helping to send signals between different parts of the brain. Scientists estimate that serotonin influences most of the brain’s 40 million cells, and due to this function, serotonin has a large impact on one’s psychological functions. In particular, serotonin is known to interact with brain cells that regulate mood, appetite, sleep, memory and learning, body temperature, and some social behavior. When serotonin activity or serotonin levels are disrupted, a person’s psychological state can be altered; this kind of phenomenon is often seen in disorders such as depression and schizophrenia.

This image shows how serotonin is synthesized in the dorsal raphe, and moves throughout the brain, focusing in the frontal cortex.         

Serotonin and Crime

The connection between serotonin and criminal activity is quite clear. Criminals have been found to have a smaller frontal cortex and a smaller amygdala. The central amygdala is part of the section of the brain that releases corticosterone. Corticosterone activates the dorsal raphe, which increases serotonin (5-HT). The direct relationship between the amygdala and serotonin can be hindered when the amygdala is reduced in size, as seen in criminals. Criminals produce less serotonin or have serogentonic dysfunction. An abundance of serotonin can also have negative affects on people causing confusion and induced criminal tendencies. On the other hand, non-criminals have a balanced level of serotonin.

The molecular compound of serotonin (5-HT)

Furthermore, impulsive aggression, a characteristic linked with criminals, is explained through the brain being unable to regulate impulsivity. Dysfunctional interactions occur between the serotonin systems in the prefrontal cortex, which is an important mechanism in controlling aggression. This also links serotonin to certain mental disorders such as depression, suicidal behavior, and drug addiction. Serotonin hypofunction (abnormally low function) demonstrates how one can be predisposed to impulsive aggression, and therefore criminal activity. Lower levels of serotonin (5-HT) have been linked with impulsive aggression (Dongju, Kennealy, & Patrick). One whose genes were programmed to produce less serotonin are therefore more susceptible to criminal activity.

The prefrontal cortex controls behavioral aggression, and impairment of this area would increase impulsive aggression. As seen in criminal brain scans, psychopaths are born with reduced frontal cortexes, increasing their aggression. Serotonin also acts as an inhibiting action in the brain. One of its purposes is to inhibit aggression. However, if serotonergic dysfunction occurs, aggressive behaviour will not be limited, therefore inclining one towards criminal activity. No matter the type of crime, lower levels of serotonin have been linked with aggression, showing how science can be broken down to explain crime. All variations of criminal activity can be simplified down to dysfunctional serotonin. One who is simply born with a defect in their brain, impairing their serotonin production, is predisposed to crime.

The red defined part of this image are the Raphe nuclei (the neurons that make up serotonin). Mentioned in this figure are a few of the behaviors that are affected because of the level of serotonin including mood and aggression.

Connections to Chemistry

Serotonin is produced through a process known as the biochemical conversion process. The process begins when two enzymes, tryptophan hydroxylase (Tph1) and tryptophan hydroxylase-2 (Tph2) help to convert tryptophan to 5-hydroxytryptophan. Decarboxylase enzymes then help convert 5-hydroxytryptophan to serotonin.

Enzymes play a crucial role in the production of serotonin. Therefore, the kinetics behind these enzymes are important to the production of serotonin. Enzymes are responsible for catalyzing, or speeding up, chemical reactions by lowering their activation energies. Specifically, enzymes can lower activation energies by providing a template for reactants to come together, stretching the molecules of a substance, providing a proper microenvironment for a reaction or directly participating in a reaction. Enzymes are ultimately responsible for speeding up the production of serotonin. As a result, a lack of these enzymes could cause dangerously low amounts of serotonin, which could stall the communication between neurons and impact a person’s behavior and psychological state. For example, low levels of serotonin can induce depression, anxiety, post-traumatic stress disorder and attention deficit hyperactivity disorder (ADHD). In the end, serotonin enzymes are a major player in human psychiatric disorders. Thus, a dysfunction with the enzyme can upset serotonin levels, and this chemical process can induce the decision to commit a crime.

 Through the enzyme actions and structure of the brain, one can see the clear connection between serotonin and criminal activity. As mentioned, lower levels of serotonin (5-HT) has been linked with impulsive aggression, and high levels of serotonin have been linked to aggression and confusion. Low levels of serotonin are most prevalent during the winter months, explaining why some people suffer from depression during cold and dark winter months.

Meanwhile, the warmer temperatures in summertime result in higher levels of serotonin. A link can be drawn between serotonin production and thermochemistry. At higher temperatures, the rate of a reaction is increased.  At higher temperatures, the production of serotonin is increased, beyond a “normal” limit in most criminals during the summer months.

James Alan Fox carried out an experiment in Columbus, Ohio, between January 1, 2007 and

December 31, 2007. He displayed the link between crime and temperature. the peak of this graph displays that violent crimes were prominent during the summer months. An increase in temperature results in an increase of serotonin which in turn leads to an increase in crime rates.