chemistry

• Forensic


  Derived from the Latin word 'FORUM' which means 'MARKETPLACE'
• Forensic chemistry


  A branch of chemistry which deals with the analysis of evidence brought from the crime scene and subjected to standardized tests to reach a conclusion necessary in solving a case before the court
• Forensic science


  An application of scientific principles to criminal and civil laws that are enforced by police agencies in a criminal justice system
• Forensic chemist


  A person that practices forensic chemistry to aid in an investigation to solve legal problems
• Toxicology


  The scientific study of poisons, especially their effects on the body and their antidotes
• Poison


  Anything other than physical agencies which is capable of destroying life, either by chemical action on the tissues of the living body, or by physiological action by absorption into the living system
• Forensic toxicology


  A part of the science of pharmacology, which deals with the quantities and effects of various drugs and poisons on human beings
• Roles of the forensic chemist in the scientific criminal investigation

  1. Determining whether or not a place/location is a clandestine laboratory

  2. Examination of marked bills/suspects during entrapment (extortion case)

  3. Taking Paraffin Test
• Four stages of work of a forensic chemist

  1. Collection and reception of specimen for lab examination

  2. The actual examination of specimen

  3. Communication of the result of examine

  4. Court Appearance
• Ordinary witness


  State facts and may not express his opinions or conclusions
• Expert witness


  One who posses a special skill, be it in art, trade or science or one who has special knowledge in waters not generally known to men or ordinary education and experiments
• Drug


  A natural or synthetic substance that is used to produce physiological or psychological effects in humans or other higher-order animals
• Explosive


  A substance that contains a great amount of stored energy that can produce an explosion
• Poison


  Substances that can cause disturbance to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism may cause illness or death
• Arson


  The crime of intentionally and maliciously setting fire to structures or wild land areas
• Crime scene


  The place where the essential ingredients of the criminal act took place it includes setting of the crime, the adjoining places of entry and exit
• Physical evidence


  Material objects that may be left or taken from the scene of a crime by the suspect or victim, or impressions left in some materials
• Arsenic


  A historically favorite killer tool, when used as a poison, symptoms include severe stomach discomfort, vomiting and diarrhea with blood
• Cyanide


  Kills by preventing red blood cells from absorbing oxygen, resulting in a process known as "internal shortness of breath"
• Protocols for handling chemical and biological evidence from crime scene to courtroom

  1. Collection and preservation of chemical evidence

  2. Acceptable packaging containers

  3. Acceptable seals
• Protocol on custody and disposition of confiscated, seized, and/or surrendered dangerous drugs, plant sources, controlled precursors and essential chemicals, instruments/paraphernalia and/or laboratory equipment

  1. The PDEA shall take charge and have custody of all such items

  2. Physical inventory and photograph shall be conducted at the place where the search warrant is served or nearest police station

  3. Within 24 hours, items shall be submitted to the PDEA Forensic Laboratory for examination

  4. Certification of forensic laboratory examination results shall be issued immediately

  5. After filing of criminal case, the Court shall conduct an ocular inspection and the PDEA shall proceed with the destruction or burning of the items within 24 hours
• Procedure for examination of confiscated drugs

  1. Provided to forensic laboratory

  2. Final certification issued upon completion of examination

  3. Court conducts ocular inspection within 72 hours

  4. PDEA proceeds with destruction or burning within 24 hours

  5. Board issues sworn certification of destruction

  6. Alleged offender or representative allowed to observe proceedings

  7. Prosecutor informs Board of final case termination and requests court to turn over representative sample to PDEA
• Standardized tests and appropriate laboratory equipment are used in processing biological evidence and physical evidence
• Physical evidence


  Anything that proves that a crime has been committed
• The specific standardized tests used depend on the type of physical evidence
• Types of biological evidence

  • Blood
  • Semen
  • Saliva
  • Vaginal secretions
  • Fecal material
  • Hair
  • Urine
  • Bone
• Presumptive test


  A qualitative analysis that allows to identify, or confirm, the presence of a substance in a sample. The results are not conclusive.
• Confirmatory test


  Validates the results of the previously conducted presumptive test. The results are conclusive.
• Basic laboratory equipment for processing biological and physical evidence

  • Chemical analyser
  • Other drug test equipment
  • Blood, saliva and other liquid testing equipment
  • Test tube
  • Test tube holder
  • Erlenmeyer flask
  • Funnel
  • Evaporating dish
  • Bunsen burner
  • Graduated cylinder
  • Beaker
  • Calcium chloride tube
  • Clay triangle
  • Cobalt glass
  • Crucible and cover
  • Crucible tong
  • Florence flask
  • Iron clamp
  • Mortar and pestle
  • Reagent bottle
  • Burette acid
  • Burette alkali
  • Burette clamp
  • DNA testing equipment
• Drug testing methods

  • Oral
  • Urine
  • Blood
  • Hair
  • Sweat
• Tests for dangerous drugs

  • Marquis Test
  • Nitric Acid Test
  • Simon's Test
  • Duquenois Levine Test
• Blood


  A red fluid that circulates throughout the body carrying oxygen, nutrients and waste. Hemoglobin gives it the red color.
• Screening tests for blood

  • Benzidine test
  • Kastle-Mayer Test
  • Leucomalachete test
• Confirmatory tests for blood

  • Takayama Test
  • Wagenaar test
  • Teichmann Test
• Blood type


  Type O can donate red blood cells to anybody/any blood type. Type AB can receive any blood type.

  
• Antiserum


  Blood serum that contains specific antibodies against an antigen (foreign agent), such as an infective organism or poisonous substance.
• Pathologist


  Studies fluids, tissues, or organs taken from the body. Often works with a surgically removed sample of diseased tissue, called a biopsy. Performs autopsies.
• Semen/Seminal fluid

  Contains spermatozoa or sperm cells.
• Choline test for semen

  • Florence test
  • Barbeiros test
  • Acid Phosphatase Test
• Microscopic examination for semen


  Specific test for identification of sperm cells. Difficult due to factors affecting detection.