Chapter 1 forensic chemistry

forensic chem

1. ESSENTIALS OF FORENSIC CHEMISTRY AND TOXICOLOGY EDGAR MENOR, RPh

2. CHAPTER 1: INTRODUCTION Chemistry - is the science that deals with the properties, composition, and structure of substances such as elements and compounds and the transformations they undergo, and the energy that is released or absorbed during these processes. Who is the Father of Chemistry? ANS: ANTOINE LAVOISIER

3. French chemist  and leading figure in the 18th-century chemical revolution who developed an experimentally based theory of the chemical reactivity of oxygen. Coauthored the modern system for naming chemical substances. Coined the oxygen as “ dephlogisticated air”. FATHER OF CHEMISTRY

4. Defined as the branch of Chemistry that deals with application of chemical principles in accordance to the crime. It plays a very important role in crimes for its speedy investigation and in administration of justice. It is well-settled that this science has an advantage over an extracted confessions, eyewitnesses and other circumstantial evidence. It is regarded as the highest form of uncontestable and conclusive piece of evidence with the utmost legal significance. Forensic Chemist often called to render testimony in court. Why do you think that the say of a Forensic Chemist has a value? ANS: It convicts the guilty, as well as in clearing the innocent suspects, has long been recognized not only in criminal investigation and detection but also in courts of law. FORENSIC CHEMISTRY

5. SCOPE Deals with the study and application of chemical principles in the solution of problem that arises in connection with the administration of justice. Deals with application of chemistry in the identification of evidence, its physical and chemical properties. What can be the possible evidences? ANS: It includes the collection, preservation, examination and study of blood, semen, and other bodily fluids. It also includes the examination of dangerous drugs in the body. Such as liquors, dangerous drugs (ecstasy, methamphetamine, etc.) Can also be used in examination of fake and original products for the fair competition. FORENSIC CHEMISTRY

6. Other examples of examination includes: arson investigation, macro etching examination, bullet trajectory, ultraviolet examination, Deoxyribonucleic Acid or the DNA Test. Tools and marks: gunshot residues such as gunpowder nitrates, paraffin test; distance determination and firearms examination. Other objects that can be tested: Explosives, hair and textile fibers, chemical aspects of documents, glass fragments, moulage , metallurgy and petrography as applied in crime investigation. For the Forensic Toxicology deals with examination of human internal organs, food samples, water and gastric contents for the purpose of detecting the presence of poisonous substance, its dosage effects and treatment. What do you think is the killers choice when it comes to the chemicals? ANS: Arsenic What do you think is the most toxic chemical in the periodic table? ANS: Beryllium FORENSIC CHEMISTRY

7. FOUR STAGES OF THE PRACTICE OF FORENSIC CHEMISTRY Collection or preparation of the specimen Actual examination The communication of the result of the examination Court Appearance COLLECTION OF THE SPECIMEN TO BE EXAMINED The proper collection, preservation and transportation of specimens are essential in the investigation of a crime. The chemist should be the one collecting the specimen. FACTORS THAT MUST BE CONSIDERED WHEN COLLECTING SPECIMEN FOR EXAMINATION: Sufficiency of Samples Standard for comparison Maintenance of Individuality Labelling and Sealing FORENSIC CHEMISTRY

8. ACTUAL EXAMINATION OF THE SPECIMEN First step: scrutinize the specimen carefully, write all the necessary documents including the logbooks for the attainment of complete description. Second step: measure or weigh the object and all the measurements and weights should be entered in the lab book. The specimen should be placed in a proper container with complete label. Third step: examination itself which consist the chemical, physical and confirmatory test. COMMUNICATION OF THE RESULTS OF THE EXAMINATION The results of the examination conducted should be communicated with the requesting party in the form of a written report which must include an enumeration of facts. COURT APPEARANCE The written report of the Forensic Chemist is usually supplemented by testimonial evidence in a later date if the case if brought to court or the fiscals’ office. The testimonial evidence is usually given within a week, a month, or even a year. So, the chemist should refresh his/her memory by referring to his laboratory record book before presenting himself in court. FORENSIC CHEMISTRY

9. ROLE OF FORENSIC CHEMIST IN THE SCIENTIFIC INVESTIGATION As a man of science, performs lab examinations on physical evidence submitted to the crime laboratory in order to expedite the investigation of a crime by the investigating party. RESPONSIBILITIES TO BE FOLLOWED BY THE CHEMIST Conducts qualitative and quantitative determination of abused drugs as well as volatiles substances. Conducts chemical examination of explosives and or/ explosive ingredients. Conducts examination of paraffin cast and firearms to determine the presence of gunpowder nitrates. Conducts gunpowder examination on clothing for possible gunshot range. Conducts chemico -toxicological examination of human internal organs, gastric contents, blood, water, food sample and other substances. Conducts examination of fake products in cases of unfair trade competition. Conducts blood alcohol determination. Examines urine samples and other blood fluids for the presence of abused drugs,. Conducts researches related to cases being examined. Testifies and gives expert opinion in court. Gives lectures on For.Chem and chemico -toxicology in various schools, universities, police and investigating units. Responds to queries of all investigating units and render expert opinion on matters related to the application of chemical principles for the purpose of assisting investigators to develop investigative leads. FORENSIC CHEMISTRY

10. SIX GOLDEN RULES IN THE PRACTICE OF FORENSIC CHEMISTRY Go slowly Be thorough Take notes Consult others Use imagination Avoid complicated theories FORENSIC CHEMISTRY

11. HPLC (High Powered Liquid Chromatography – used for the qualitative and quantitative determination of a volatile or a non-volatile substances based on the chromatographic separation of its components. Ultra-Violet Spectrophotometer – used of qualitative and quantitative analysis of organic compounds. FORENSIC CHEMISTRY

12. EMIT (Enzyme Multiple Immuno Assay Technique – used for screening of abused urine samples. SEM (Scanning Electron Microscope) – used for the physical identification of various questioned specimens. A software-controlled digital scanning electron microscope used to produce sticking, images over a qide range of magnification on rough or covered surfaces of minute specimen such as hair, fibers, paint particles, drugs, metals, etc. FTIR (Fourier Transform Infrared Spectroscopy) – used for identification of pure organic substance. The resulting spectrum could be referred to as the fingerprints of the substance. FORENSIC CHEMISTRY

13. THANK YOU FOR LISTENING!!! MUCH LOVE