Heroin is an illegal odourless, bitter crystalline compound { C17H17NO(C2H3O2)2 }. It is a highly addictive narcotic and rapidly acting opiate (a drug that is derived from opium). Heroin is processed from morphine, which is the major component of opium. Opium is natural substance that is extracted from the seed pod of certain varieties of poppy plants. Heroin is also called diamorphin. Pure heroin is a white powder, but the street heroin is a brownish-white powder that can be smoked, snorted or dissolved and injected. Heroin is rapidly metabolized into morphine by removal of the acetyl groups. It is the morphine molecule that then binds with opioid receptors and produces the subjective effects of the heroin high. Heroin is therefore a prodrug, which is a depressant that inhibit the central nervous system. Much larger doses can make users relaxed and drowsy.
Below is the structure of heroin (Harrison, 2006)
C21H23NO5
The presence of quinine in a substance can be examined using a UV light. The UV light is a light that is made up of a powerful lamp containing the ultra-violet, visible and infrared components of light. It filters down the light into individual colour bands (wavelengths) that enhance the visualization of evidence by light interaction techniques including fluorescence (evidence glows), absorption (evidence darkens), and oblique lighting (small particle evidence revealed).The UV light is an electromagnetic radiation in the wavelength of range of about 4 x 10-5 to 5 x 10-9 m, placing it between visible light and X rays in spectrum. UV is non-ionizing radiation but within cells; it can cause chromosome break. In nature, most organisms are protected against UV. The UV light is used to determine the potential toxicology in a substance, i.e. the effect of the chemical substance on living organism. Some substance fluorescence or emit light when they are exposed to UV radiation; the intensity of the fluorescence indicate the concentration of the material. The presence of quinine is determined when a material fluorescence, if it emits light then, quinine is not presence. UV (Ultraviolet) light is radiation energy in the form of invisible light waves; it is emitted by the sun and by tanning lamps. (Hodgson et al, 1998, pg 481)
In forensic cases, Blood, urine and hair samples are the most common sample used for drug testing. Urine samples might not contain the toxic substance an individual was influenced by at the time the sample was collected because some drug stay longer in the body, for example, in a heavy user of marijuana, it take up to 14 day following the use before it is removed from the body. Toxicologists are provided with a profile of substance that an individual was influenced by or at the time of collection in blood sample. Therefore, it is often used to measure blood alcohol content in drunk driving cases. Hair records a longer intake of drug abuse from medium to high dosage; it takes about 3 month after use to remove the substance from the hair. Therefore hair can not be used to give a precise time, date or dose of drugs identified, but it can give pattern of usage.
The aim of this experiment is to broaden our understanding on the use of basic toxicology and the basic quantification in forensic investigation; to know how to evaluate the value of toxicological specimens as an evidence in forensic case by observation and further reading; to develop an understanding of the use and the value of toxicological tests in forensic case; finally to improve our knowledge of the identification of toxicological substances in body fluids.
The materials used are:
Reagents: Chloroform, Potassium Hydroxide (saturate aqueous solution), Quinine Sulphate stock solution, (100mg of quinine sulphate in 1 litre distilled H2O), 0.05M Sulphuric acid (2.8ml conc H2SO4 in 1 Litre distilled H2O).
Samples: Urine1: Control sample of Urine with quinine
Urine 2: Control sample of urine without quinine
Unknown Urine: Exhibited urine sample taken from driver in scenario
Quinine Sulphate (5 different concentrations)
Tap water
Tonic water
METHODS
During this experiment, six samples were examined by three groups, i.e. 2 samples per group. Contamination of samples was brought to a minimal by rinsing funnel thoroughly with water and taking general precaution.
During the preparation for this experiment, 6 tubes were labelled with the title of the samples that is been processed using a permanent marker; 5ml of the relevant samples was transferred into the appropriately labelled tube (i.e. 5ml of quinine sulphate into the tube labelled QS). Then the alkalinity was adjusted by adding drop of saturated potassium hydroxide to each of the samples; the alkalinity of each of the samples were tested with pH paper by dipping the paper into the fluid and comparing the colour produced with the reference colours on the side of the pH paper book / vial; drop by drop of the saturated potassium was added testing the pH after each drop until the pH was greater than 7.
Then the samples were extracted: one of the samples was decanted into a separating funnel; 10ml chloroform was added and the funnel was shook for at least 1 minute; then the separating funnel was placed in a hole on the test tube rack with the top pointing downwards and liquid was allowed to separate into two layers; after which, the lower (chloroform) solvent layer was transferred to a clean separating funnel and the upper aqueous layer was discarded. 6ml of 0.1 N sulphuric acid was added to the separating funnel; the upper (aqueous) layer was transferred into a test tube. Each of the six samples was extracted using this method.
Each of the six samples was examined under UV light in order to determine whether they fluorescence or emit light.
The result was recorded and the samples that do fluorescent were compared to the reference samples.
THE RESULT
The result of test for alkalinity shows that tonic water turn bluish green, with pH12 and Quinine sulphate turned blue with pH14.
The results are recorded below listing the most fluorescent sample at the top and the least fluorescent at the bottom. The percentage of each sample was determined by comparing each sample to the referenced sample.
This shows that tonic water has the most fluorescent (90%) and quinine sulphate has 80%. Urine 1 showed little fluorescent, so we were unable to determine the percentage; Urine 2, Unknown Urine and water showed no traces of fluorescent.
DISCUSSION
The aim of the experiment was to test for the present of quinine in the given samples.
From the experiment, some of the samples fluorescence while some didn’t; this might be because of the absence of quinine in some samples or the experiment was not carried out properly. Comparing the result of the experiment with the expected result, one can say that the experiment was not carried out properly on Urine 1 sample because we were unable to decide the percentage of the present quinine in the sample, even though it showed little fluorescent. Furthermore the unknown urine was supposed to fluorescent, but it didn’t; as a result, the presence of quinine in the sample was not proven. These might be because of inadequate saturated potassium hydroxide was not added during the test for alkalinity or less/ more chloroform was used or the chloroform was not allowed to mix with the sample before it was discarded.
The other samples met the expected result because the given procedures were followed. Some samples did not meet the expected result because the given instruction was not followed properly.
Comparing the results of the experiment performed on tonic water with already published experiment on the determination of quinine in commercial soft drink (Tonic water) using molecular fluorescence spectroscopy (Molecular fluorescence spectroscopy is based on the emission of light by molecules, which are excited to emit their characteristic spectra by exposure to UV light of specific wavelengths. The wavelength at which a molecule may be excited to emit is referred to as the excitation wavelength, and the spectrum emitted by the sample the emission spectrum) by de Lloyds (1996); tonic water contain a certain amount of quinine, which make it fluorescence when exposed to UV light. Lloyds performed is experiment using the technique of fluorescence spectroscopy to determine the percentage of quinine content in commercial samples of tonic water/bitter lemon. 5mL or 10mL microburette and a 50mL burette were used to prepare a standard and sample solutions. A standard quinine sulphate solution containing 10mg of quinine sulphate in 1Litre of distilled water was provided.
The microburette was used to transfer 0.5, 1.0, 1.5, 2.0, and 2.5mL respectively of the standard quinine sulphate solution to 25mL volumetric flasks, labelled 0.2, 0.4, 0.6, 0.8, and 1.0ug/mL respectively. Using the 50mL burette, sufficient distilled water was added to each flask, so that the total volume in each is 12.5mL, then each flask was filled to the mark with 0.2N sulphuric acid, to give a final concentration of 0.1N acid for optimal fluorescence. The solutions were mixed thoroughly. A sample of commercial tonic water was obtained and a diluted sample as above was prepared a diluted. Then, two cuvettes were carefully rinsed; one filled with all the standard/ test solutions (sample) and the other with 0.1N sulphuric acid (reference). then, the measurements of all the standards/test solutions with the excitation wavelength setting at 350 nm and the emission wavelength setting at 450 nm, with the appropriate scale expansion for optimum signal/noise ratio was Carried out.
He found out that commercial soft drink (tonic water) contain quinine which fluorescent.
In forensic investigation, UV light is very good for detecting semen, saliva, and blood, even in diluted concentration. In the test for the presence of quinine in urine or tonic water, UV light is good because if quinine is present, the sample appears to be blue. The use of UV light can be of great help in many forms of forensic investigations. In this experiment, UV light has been to determine the presence and percentage of quinine in the given samples, i.e. UV light is useful in forensic for determining the period / time drug was used.
Issues to consider in toxicology
Toxicity of a substance is not all determined by its inherent toxic properties but also by different factors relating to the individual exposure. Some of these factors are discussed below and the issues to consider in toxicology.
Contamination: several criminal cases has been brought to dishonour because the issue of contamination of physical evidence. Webster’s Dictionary defines contamination as; “to make impure, corrupt, by contact; pollute, taint.” Potential contamination of physical evidence can occur at the crime scene, during the packaging, collection and transportation of the evidence to a secured facility or laboratory, and during evidence analysis and storage. (Baldwin & ) Protocols to identify and reduce the risk of contamination have been developed in forensic investigation; this includes collection, packaging and transportation of evidence. For example, when collecting a liquid blood sample; a sterile pipette with teat or syringe is used, if blood is partially clotted, lift on a sterile, disposable blade. To package and transport it: a carefully labelled dry sterile plastic bottle or tube including biohazard warning is place into a carefully labelled and sealed protective secondary packaging with a biohazard warning is used. It is stored in the freezer.
The level of contamination risk to be expected in evidence is related to the type of crime scene and the number of individual present and individual handling the evidence or sample. Other factors that contribute to contamination of evidence includes poor scene control, poor collection technique, weather condition, airborne condition in the laboratory; for example, filters in the air conditioning unit, mistake during experiment or test, etc.
In this experiment, contamination was brought to a minimal by rinsing funnel thoroughly with water and taking general precaution. This necessarily doesn’t means that the samples were not contaminated because while rinsing the funnel in between samples, some water might be lift in the funnel, or the funnel might not be thoroughly rinsed, which means that some solution might still be left in the funnel, therefore, this might contaminate the evidence. The level of contamination might be brought to a minimal by using two separate funnels for the experiment instead of rinsing in between.
The issue of contamination is an essential issue that most be put into consideration in forensic investigation because when a sample or the process of an experiment is contaminated, the result gotten from the sample, might not be accurate. As a consequence, the result will not be accepted in the court of law due to contamination; since the quality of the evidence in criminal cases is scrutinized in the courtroom. Both defence and prosecuting attorneys look to the manner in which evidence is collected and handled to strengthen their cases.
Tolerance: the issue of tolerance has to be taken into consideration in forensic investigation because it could be misleading; when an individual is repeatedly exposed to a particular substance, the dose must either be increased or given more frequently to have the same effect as when it was first used; that is, the more frequently a drug is used, the more likely the individual is to build up tolerance to the drug (to produce the same toxicological effects, more of the drug is needed). For example, a person abusing methamphetamine may get high from 10-mg dose, after several days; in order for him to get high at the same level he will need 20-mg. then it go on and on. If a person becomes tolerant to a drug, it means that he can tolerate even larger quantity of the drug without having dangerous reaction. (Siegel, 2007, pg 415-416)
Drugs like amphetamines, benzodiazepines and opiates, e.g. heroin and morphine, (which contains quinine) might lead to the development of tolerance. When an individual stop taken the drug for a period of time, tolerance may be lost; if the individual resume the drug habit at the same level as it was previously tolerated, the result might be serious or deadly. The most vulnerable people are heroin users returning to the habit after a period in prison. (Jackson & Jackson, 2004. pg 191) when a person dies and a large concentration of drug is found in the bloodstream, the drug history of person has to be examined before making a conclusion as to the role of drug in the death – since, a high concentration necessarily does not mean that the drug caused death.
In drugs like marijuana, there is a reverse tolerance effect because the symptoms resulting from it are learned behaviour, that is, the more a person smokes, the more the effect will be expected. Tetrahydrocannabinal, an active ingredient in marijuana may remain in the body for months after ingestion and the regular use will increase the concentration and effect. Therefore, If a sample of a individual who takes marijuana is taken, it will be difficult to judge the last time of use.
When analysing the sample of urine in the experiment, tolerance is an important factor to consider because the time of consumption and how often the person uses a quinine drug will help to determine if the person is still under the influence or not. Also it will help to know how long the person has taken the drug and might help to determine how long it will take for the drug to be eliminated.
Accumulation: according to Jackson & Jackson (2004. pg 191) the half-life is the time taken for the concentration or amount of a poison in the body (or given part of the body) to halve. This means that there is still half of the concentration in the body when another dosage is taken, this will lead to accumulation of the drug. Some accumulative poison (like lead, mercury and metalloid arsenic) have half-life, which is long enough to allow chronic exposure to assist toxic doses, which leads to accumulation of the poison within the body. If both the rate of intake is sufficiently high and the half-life is long enough, the amount of poison in the body will eventually become large enough to cause sickness or death.
In forensic investigation, this is important in a sudden death because the person might have died of accumulation of poison. Furthermore in the case of drug, the test might should signs of drug even though the person hasn’t had any because the drug is accumulating.
Sensitisation: This has to be considered because prior exposure to drugs may lead to the development when a person encounters it a second time. This is symbolized by an enhanced immune response. If the immune response is excessive or inappropriate; the condition is hypersensitivity and is demonstrated by anaphylactic shock (shock caused by allergic reaction), which may result in the death of the person. (Jackson & Jackson, 2004. pg 191)
In order to improve this experiment, the appropriate procedure would be followed to avoid mistake. This is because the result gotten from some of the sample does not correspond with the reference result. Also, to improve this experiment; contamination needs to be avoided in every way possible, i.e. Enough sterile materials should be provided for every table, so as to reduce cross contamination.
Conclusion
Next time, if the procedure is properly followed we will be able to achieve a corresponding result. This means that the experiment was precise. Precision refer to how closely the experiment would match one another if repeated under the same condition.
Accuracy refers to how close an experiment is to the real value. The experiment was accurate because the aim of this experiment was met; which was to test for the presence of quinine in the given samples. Also the result taken from the experiment was compared with the reference sample; the expected result was met, except in urine 1 and the unknown sample, which could be improve by following the instructions carefully.
This experiment was able to broaden our understanding and the importance of toxicology in forensic; by explaining and experimenting how toxic substance affect human. A Swiss physician and philosopher Paracelsus (1493 -1541) (citied in Jackson & Jackson, 2004. pg190) once stated that ‘All substances are poisons; there is none that is not a poison. The right dosages differentiate a poison from a remedy’. These means the toxicity of a substance is linked with the dosage, i.e. the amount of dose taken dictate the effect on an individual.
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