forensic

1. FORENSIC CHEMISTRY AND TOXICOLOGY
MODUL
E
THE NATURE OF BLOOD
 Blood – is highly specialized circulating tissue consisting
of cells, enzymes, proteins, and inorganic substances
suspended in fluid medium.
o Volume: About 8% of total body weight
 5 to 6 liters (Male blood)
 4 to 5 liters (Female blood)
o Components of Blood:
Plasma (55%) - fluid portion composed
principally of water and other constituents
such as enzymes, glucose, etc.
Cells (45%) – solid portion consist of red
blood and white blood cells and platelets.
RBC (erythrocytes) – carry respiratory
gases and give it its red color because they
contain hemoglobin – an iron-containing
protein that binds oxygen in the lungs and
transport it too tissues in the body.
 WBC (leukocytes) – fight disease.
 Platelets (thrombocytes) - cell fragments
which play an important part in the clotting of
the blood.
Objectives:
a) Understand the nature of blood and be able to determine the
origin of blood by conducting various test
b) Demonstrate skill in collecting, preserving, and transporting of
blood specimen.
c) Understand Forensic Serology and apply skill on proper handling
and examining seminal fluids.
CHAPTER 3: FORENSIC SEROLOGY/
FORENSIC BIOLOGY
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2. FORENSIC CHEMISTRY AND TOXICOLOGY
MODUL
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Before20th
century
Karl
Landsteiner
(1901)
Rhesus (Rh)
factor (1937)
Until early
1990s
o Blood Loss:
 40% loss, internally or/ and externally, is required to produce irreversible
shock (death).
 blood loss of 1. 5 liters, internally or externally, is required to cause
incapacitation.
o Blood Clotting: when a protein in the plasma
called fibrin traps and enmeshes the red blood
cells, the blood clots forming solids that separates
the serum.
Serum – is the remaining pale-yellowish liquid
when the clotted material where removed from the
blood.
 This yellow liquid contains certain protein
known as antibodies.
The serum that contains antibodies was called –
antiserum.
BLOOD GROUPING
announced typing of blood. This classification also called the A-B-O
system. On 1930, he received a Nobel prize award for his work in
blood typing
another blood factor discovered. At present more than 100 different
blood factors shown to exist
physicians have tried to transfuse blood from different blood from
one individual to another. Their attempt often ended in failure
because the transfusing sed blood tended to coagulate in the body
of the recipient causing an instantaneous death
forensic scientist uses blood factor technique in linking blood to the
person originates this blood
History of Blood Grouping
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3. FORENSIC CHEMISTRY AND TOXICOLOGY
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o In theory, no two individuals except for identical twins, could be expected to have
the same combinations of factors.
o A-B-O SYSTEM: classification of blood based on the presence or absence on
inherited antigen on the surfaces of red blood cells (RBCs).
o Antigens are defined as substances recognized by the body to produce an
antibody to react specially to it
o Antibody is a protein that destroys or inactivates a specific antigen. Usually
denotes using the prefix “anti”.
 PETER J ADAMO THEORY
o Blood type A – folk had ancestors that were farmers, hence they ought to be
vegetarians and shun meat and dairy products.
o Blood type B – folk had descendants that were nomads, hence they should eat
red meat and fish.
o Blood type O – had ancestors that were hunters and gatherers, hence they should
have lots of animal protein and little carbohydrates.
o Blood type AB – mixed ancestry, hence they should have a combination of type
A and type B.
 Test for the presence of blood
A. PRESUMPTIVE TEST FOR BLOOD
1. Spot test Procedure Result Remarks
Benzidine test Add 3 drops of
hydrogen
peroxide to
blood stain then
add benzidine
reagent
Blue
coloration
An enzyme
peroxidase in
blood causes
the benzidine to
be oxidized to a
polymer which
is blue colored.
Kastle-Meyer/
phenolphthalein
test
First a few drops
of ethanol, then
a few drops of
phenolphthalein
and finally a few
drops of
hydrogen
peroxide are
dripped onto the
sample.
Sample
turns
violet
Phenolphthalein
and hydrogen
peroxide react
with the
hemoglobin in
the blood; the
alcohol
behaves as a
solvent.
Guaiacum test/
Van Deen’s
day’s or
Schonbein’s
test
A drop on
tincture of
guaiac,
turpentine and
ether of
hydrogen
peroxide.
Blue
coloration
Do not react
tovery old stain
but sensitive to
1:50T
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4. FORENSIC CHEMISTRY AND TOXICOLOGY
MODUL
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Hemastix Test strip used
for field test of
blood by
moistening with
distilled water
and placed in
contact with
blood.
Color-
bands
are
present
Test kit for
blood
Luminol test This is viewed
under ultraviolet
lamp producing
bright violet
coloration.
Bright
blue
A spray reagent
used to test for
the presence of
blood is not
visible under
ordinary light.
Leucomalachite
green test
(Adler 1904)
Leucomalachite
reagent and
hydrogen
peroxide is
added to blood.
Malachite
green or
peacock
blue
Not a sensitive
as benzidine
test.
Leucomalachite
is oxidized to
malachite
green.
2. Microcrystalline
Test
Procedure Result Remarks
Teichmann/
Hemin
crystal test
Salt and acetic is
added to stain and
acid is allowed to
evaporate.
Reddish
brown
rhombic/
prismatic
crystals
Crystals of
hemin or
hematic
crystals
Takayama test /
Haemochromogen
crystal
Add Takayama
reagent to stain
Large rhombic
crystals with
salmon color
Test for
hemoglobin
Acetone-Haemin or
Wagenhaar Test
Acetone and
oxalic
Small dark
dichroic
crystals
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5. FORENSIC CHEMISTRY AND TOXICOLOGY
MODUL
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B. CONFIRMATORY TEST FOR BLOOD
1. Microscopic Exam – examination of menstrual blood corpuscles to
differentiate mammal blood to other animals
2. Spectroscopic method – characteristic absorption band to Frauen Holfer
lines
 Test to determine whether the blood is of human origin
Test Procedure Result Remarks
Precipitin test Use human blood and
rabbit to create
sensitized rabbit
serum. This will form a
precipitin band on the
junction between the
serum and human
blood being tested
Blood
agglutinates
Blood stain
dried as long
as 10 -15
years or more
may still give
a positive
precipitin
reaction.
Gel diffusion Using agar subjected
to electrical potential
Blood
forming line
or bands of
reacted
antigen and
antibody
Electrophoresis An electrical potential
to a gel medium until
antigen and antibody
reacts
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6. FORENSIC CHEMISTRY AND TOXICOLOGY
MODUL
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COLLECTION, PRESERVATION AND
TRANSPORT OF BLOOD SPECIMEN
 Blood is a perishable substance; thus, it is essential that proper collection and
preservation were given attention so as not to destroy the evidence.
 Liquid sample should be placed on a sterile container and the stopper was sealed
with a masking tape.
 Dried stains in smooth surface should be scrape with a clean knife or razor blade
and placed the scrapings in an envelope, pillbox, or folded paper pocket.
 Clothing containing stains should be air dried without sunlight (some component
might damage by direct
sunlight) and wrapped it with
paper.
 If the blood is in soil,
same is applied as in the
collection of debris, put it in
a glass container or new
paint can and maintain
individuality and chain of
custody.
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7. FORENSIC CHEMISTRY AND TOXICOLOGY
MODUL
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FORENSIC CHARACTERIZATION OF SEMEN
 Semen – viscid gelatinous, sticky character
but after exposure teds to become more
liquid due to enzyme action, normal
quantity in a single ejaculation is 1.5 to 3.5
ml.
 This contain spermatozoa, epithelial
cells and crystal choline and lecithin and
slightly alkaline.
 Spermatozoa – healthy young man is
about 400 to 500 ml
 Aspermia/ Oligospermia – sperm
disease
 Examination of semen and seminal stains
 Physical examination:
 Microscopic examination - the sperm cell was stained and viewed under
a high-power microscope.
 Ultraviolet examination – seminal stain exhibit bright bluishfluorescence.
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8. FORENSIC CHEMISTRY AND TOXICOLOGY
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 Chemical examination
 Florence test – named after introduction of Dr Florence of Lyons, France for
this test. Based on formation of choline periodize crystal, a dark
brown rhombic or needle shape.
Limitation for this test includes:
 If the specimen was not dried carefully destroying choline.
 If the specimen were mixed with blood.
If the specimen contains too much albumen that interfere in the
reaction.
Barberios test – spermine picrate, a slender yellow tinted
rhombic needle with obtuse angles and sometimes appeared
as ovoid crystals.
Acid phosphatase – Dr Sidney Kaye, a specific
sperm test for human, forming orange-ed pigment
(a naphthylamine and Fast blue B reagent)
NOTE: the more semen, the deeper the purple
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9. FORENSIC CHEMISTRY AND TOXICOLOGY
MODUL
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FORENSIC ENTOMOLOGY
 Forensic entomology is a branch which makes use of insects in the detection of crime
and used to calculate the time since death.
 Why used insects in death investigation?
 Insects are generally the first to discover a corpse.
 Insects arrive at a decomposing corpse in somewhat predictable sequence
“ecological succession”
 Often insects are ignored or even discarded as evidence at a death scene
or autopsy.
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10. FORENSIC CHEMISTRY AND TOXICOLOGY
MODUL
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 BLOW FLY LIFE CYCLE
Adult female blow flies arrive within
minutes to lay eggs on a cadaver.
Each deposit about 250 eggs in the
natural openings of the body and
open wounds. The eggs hatch into
first-stage maggots within 24
hours. These feeds and then molt
into second-stage maggots, which
feed for several hours, and then
molt into third-stage maggots.
Masses of third-stage maggots
may produce heat, which can raise
the temperature around them more
than 10° C. After more feeding, the
third-stage maggots move away
from the body and metamorphize
into adult flies.
 It can be divided in three subfields: urban, stored-product and medico-legal/ medico-
criminal.
 Urban forensic entomology concerns pest infestations in buildings or gardens
that may be the basis of litigation between private parties and service providers
such as landlords or exterminators.
 Stored-product forensic entomology is often used in litigations over infestation
or contamination of commercially distributed foods by insects.
 Medico-legal forensic entomology includes arthropod involvement in events
such as murder, suicide, rape, physical abuse and contraband trafficking. In
murder investigations it deals with what insects lay eggs when and where, and in
what order they appear in dead bodies. This can be helpful in determining the
time or postmortem interval (PMI) and location of the death in question.
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11. FORENSIC CHEMISTRY AND TOXICOLOGY
MODUL
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1235AD
 HISTORY OF FORENSIC ENTOMOLOGY
Sung Tz’u – Chinese death investigator wrote a book entitled “The
Washing Away of Wrongs” probably the first actual medico-criminal
entomology case was recounted.
A murder by slashing occurred in Chinese Village, and
the local death investigator was deputized to solve the
crime. After some fruitless questioning, the investigator
had all villagers bring their sickles to one spot and lay
them out before the crowd
Flies were attracted with one of the sickles, probably
because of invisible remnants of tissue still adhering to it,
and the owner subsequently broke down and confessed
to the crime
In other portions of the text, Sung Tz’u
demonstrated knowledge of blow fly
activity of bodies relative to those orifices
infested, the time of such infestation, and
the effect of trauma on attractiveness of
tissue in such insects
Insects of forensic importance is
necrophagous (corpse-eating). This is
outlined by Mostovski and Mansell. The
order in which the insects feed on the
corpse is called the faunal succession
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12. FORENSIC CHEMISTRY AND TOXICOLOGY
MODUL
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TOPIC LINK FOR VIDEO
Human Blood Video | Blood
Components | Blood Cells
https://www.youtube.com/watch?v=qrE6Y0Se8b
w
Structure of a Sperm Cell
https://www.youtube.com/watch?v=_Mum9z-
8kks
Forensic entomology | The crime scene https://www.youtube.com/watch?v=HIVKISCmjT
Q
References:
Viccelio, Peter, Emergency Toxicology, 2nd Edition, Lippincott-Raven Publishers, 227 East Washington Square,
Philadelphia, 1998
Sunico, Lorenzo A, Forensic Chemistry, NBI, Manila.
Saferstein, Richard D, Criminalistics: An Introduction to Forensic Science, 2001. Prentice Hall, Upper Saddle
River New Jersey
Eckert,William, G, Introduction to Forensic Sciences, CRC Press, New York 1997
https://www.nlm.nih.gov/exhibition/visibleproofs/galleries/technologies/blowfly.html
LINKS
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