FORENSIC 3 CHEMISTRY AND TOXICOLOGY

CHEMISTRY

Branch of science that deals with matter

FORENSIC CHEMISTRY

Application of chemistry to law enforcement

TOXICOLOGY

Branch of science that defines the natute, effects and detection of substance that is present to specific matters

FORENSIC TOXICOLOGY

The use of toxicology principles to aide medico legal investigations of deaths and poisoning

FORENSIC SPECIALIST

A person that practices forensics such as; DNA EXAMINER, BALLISTICIAN, FORENSIC PHOTOGRAPHER AND ETC.

FORENSIC CHEMIST

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

THE FORENSIC CHEMIST AS AN EXPERT WITNESS IN COURT

Following qualification

1. Education

2. Training

3. Experience

6 GOLDEN RULES IN THE PRACTICE OF FORENSIC CHEMISTRY

GO SLOWLY - goodwork cannot be hurried

BE THOROUGH - make careful and minute examination of everything and do not be satisfied

AVOID COMPLICATED THEORY - the simplest explanation is the most likely to be the right one

CONSULT OTHERS - He should consult those who are most likely to know

USE IMAGINATION - which enable inference ( understand from clues) and deductions.

TAKE NOTES - keep a full neat and clean record

REAL / AUTOPTIC EVIDENCE

Intended to prove a fact in issue based on its demonstrable physical characteristics

TESTIMONIAL EVIDENCE

An expert may be placed on a witness stand and answer all the question

EXPERIMENTAL EVIDENCE

An expert required to perform experiements to prove a certain matter of fact

DOCUMENTARY EVIDENCE

Any written evidence presented by an expert in court (technical report findings)

“GUIDING PRINCIPLES IN THE COLLECTION OF PHYSICAL EVIDENCE”

SUFFICIENCY OF SAMPLE

Sufficient weight, volume, or pieces of sample for analysis

STANDARD FOR COMPARISON

A standard should be submitted so that a comparative analysis can be performed.

MAINTENANCE OF INDIVIDUALITY

Should be packed individually to prevent contamination

LABELING AND SEALING

Should be labaled and sealed properly to avoid confusion

CHAIN OF CUSTODY

Refers to a written record of all the individuals

It follows the order:

Scene

Evidence

Evidence collector

Forensic examiner

Evidence custodian

Court presentation

“CLASSIFICATION OF FORENSIC EVIDENCE”

EVIDENCE RECOGNITION

Recognition of pieces of evidence in the crime scene

CLASSIFICATION

To place thing into groups according to their basic characteristics

INDIVIDUALIZATION

Demonstration that an object is unique

RECONSTRUCTION

Process of putting together evidence available

“EXAMINATION OF BLOOD”

BLOOD

Carries oxygen and nutrients to all parts of the body

RED BLOOD CELLS (ERYTHROCYTES)

• The most abundant cells in our blood

• Contain protein called “HEMOGLOBIN” that carries oxygen to our cells

HEMOGLOBIN

Carries oxygen to our cells

WHITE BLOOD CELLS ( LEUKOCYTES )

• Part of the immune system and destroy infections agents called PATHOGENS

• Source of DNA

PLATELETS (THROMBOCYTES)

Clothing factors called coagulation to seal a wound snd prevent a loss of blood

PLASMA

Yellowish liquid portion of blood

“COLLECTION AND PRESERVATION OF BLOOD”

FLUID BLOOD

Usually collected from victims of crime of violence, parent and child in case of disputed paternity

DRIED BLOOD

Collected from smooth surface like wall, frames, or clothing

THE COLLECTION AND PRESERVATION OF BLOOD

“EXAMINATION OF BLOOD SPECIMEN”

PRELIMINARY TEST

• Used to demonstrate the presence of blood

• Presumptive or color test

BENZIDINE TEST

The most sensitive of all preliminary test

Positive result : INTENSE BLUE COLOR

PENOLPTHALEIN TEST (KASTLE MAYER TEST)

Alternative test to benzidine

Positive result : ROSE COLOR or DEEP PINK

Most common test

CONFIRMATORY TEST

Test that positively identified blood

TAKAYAMA TEST (CONFIRMATORY TEST

produces pink/salmon-colored hemochromogen crystals.

TEICHMANN TEST (CONFIRMATORY TEST(

produces brown hemin crystals.

SPECTROSCOPIC TEST (CONFIRMATORY TEST)

Most delicate and reliable test for determination of the presence of blood in both old recent stains

PRECIPITIN TEST

Determine whether blood is a human or non-human origin

BLOOD GROUPING TEST

Determines the blood group of human

AGGLUTINOGEN OR ANTIGEN

Stimulates the production of agglutinins or antibodies

ANTIBODY OR AGGLUTININ

Cause agglutination or clumping together of the red bloods cells

DNA TEST

Matching it with a standard (comparison)

ARTERIAL BLOOD

Bright scarlet in color

VENOUS BLOOD

Dark red color

“EXAMINATION OF SEMEN”

SEMEN

Albuminous fluid with faint grayish yellow color, and containing SPERMATOZOA

SPERMATOZOON

A living organism, consisting of a head, neck and tail.

GROSS EXAMINATION

Inspection by means of the naked eye or with the use of the hand lens

* Inspection by means of UV light

• show bluish fluorescence

BARBERIO’S TEST (SEMEN)

Place under microscope and needle shape crystals with yellow color is produced

FLORENCE TEST (SEMEN)

Crystals are darkbrown in cluster

PURAMEN REACTION → (positive result)

• yellow precipitate of spermine

• Cross like crystals

ACID PHOSPHATASE TEST (SEMEN)

Deep purple

“EXAMINATION OF GUNPOWDER

GUNPOWDER OR PROPELLANT

• black powder

• Smokeless powder (common used)

• Semi - smokeless powder

POSSIBLE LOCATION OF NITRATE WHEN THE PROPELLANT EXPLODES

• barrel of the gun

• In or around the wound

• Clothing

• Hand of the person firing the gun

GUNSHOT WOUND (GSW)

1. CONTACT - gun muzzle pressed against, or within an inch or two of the body

2. CLOSE DISCHARGE - 6 inch to 2ft.

3. DISTANCE DISCHARGE - over 2ft or 3ft

“DETERMINING PRESENCE OF GUNPOWDER”

PARAFFIN TEST

• To extract the nitrates embedded in the skin

• Will appear as BLUE SPECKS

NEUTRON - ACTIVATION ANALYSIS

Most reliable test for detection of gunpowder nitrates

HAIR

Specialized epthelial outgrowth of the skin

PART OF THE HAIR

• ROOTS - Portion embedded in the skin

• SHAFT - Portion above the surface of the skin

• TIP - end of an uncut hair

PARTS OF THE HAIR (SHAFT)

• CUTICLE - outermost covering of the hair

• CORTEX - intermediate and the thickest layer of the skin

• MEDULLA or CORE - most characteristic portion of the hair CENTRAL CANAL

Medullary index less than 0.5 human origin

Medullary index greater than 0.5 animal origin

“ANALYSIS / TESTS FOR GLASS”

SPECTROGRAPHIC TEST

Shows the constituent elements of a glass

X-RAYS / DIFFRACTION ANALYSIS

Determine the type of pattern of glass

3R’s RULES FOR RADIAL FRACTURE

Radial crack will be at right angle to the REAR side

RFC RULE FOR CONCENTRIC FRACTURES

Concentric crack will be at right angle to the front side

MOULAGE

• An impression or cast made

• Used casting material (plaster of paris)

TOOL MARKS

• COMPRESSION MARKS - impression of a single blow

• FRICTION MARKS - series of scratches or striations

ETCHING FLUID

Fluid used to restore tampered serial numbers

“DANGEROUS DRUG AND FORENSIC DRUG ANALYSIS”

QUANTITATIVE DRUG EXAMINATION

Knowing the degree of its purity

QUALITATIVE DRUG EXAMINATION

Presence of the dangerous drugs

TOXICOLOGY

Scientific study of poisons

“CLASSIFICATION OF POISON”

VEGETABLE POISONS

Poisons that comes from plants

ANIMAL POISONS

Poison transferred through bites and stings

MINERAL

Strong acids and bases

MICROBIAL

Poison produced by microscopic organism

SYNTHETIC

Chemically produced in laboratory

NATURAL POISONS

Are found naturally in nature