Abstract:
Rapid advancement and growth in the
medical field have led to tremendous
improvement in the field of research
and technology. Today, one can easily
detect even minute differences
between twins or parents and their
children. Whether it is on-site
detection of the culprit or real-time
DNA analysis, all these have become
just a matter of a few hours by the
'forensic chemistry'. It is gaining
immense recognition and popularity
with each passing day. It involves
collecting the data and analysing the
evidence from crime scenes and other
locations to produce unbiased
conclusions that can help with the
investigation and conviction of
criminals or exonerate an innocent
person from suspicion.
Keywords:
Organic compounds; Forensic science;
Finger print applications; anti Counter
feinting.
Introduction:
The use of scientific procedures in
criminal proceedings is known as
forensic chemistry. Specialists in this
field have a wide array of methods and
instruments to help identify unknown
substances. These include the use of
high-performance liquid
chromatography, gas chromatography-
mass spectrometry, atomic absorption
spectroscopy, infrared spectroscopy,
and thin layer chromatography. The
spectrophotometer is used for
determining the concentration,
molecular weight, and composition of
the compounds by measuring the
absorbance capacity of the solution.
History of Forensic Chemistry
One of the very first significant
advancements in forensic chemistry
was made in 1836 by British scientist
‘James Marsh'. He developed the
Marsh test for the detection of arsenic,
which was then successfully applied in
a murder prosecution.
The "father of toxicology," Mathieu
Orfila, also made significant
contributions to the discipline in the
early 19th century. A process
highlighted by many television
detective shows, forensic analysis
relies on scientific techniques and
deductive reasoning to determine
previously unknowable facts, often in
relation to crimes. When trying to
solve a case, forensic analysts will
examine both organic and inorganic
evidence.
Forensic Analysis
Forensic analysis is often used to help
solve crimes and contains within the
umbrella term many more specialized
types of analysis. Serology involves
the analysis of human fluids, for
example, and can be used to determine
the presence of DNA, while hair and
fiber analysis can determine such
complex traits as diseases and race,
though the results are not always
clear. These are both types of organic
analysis. Inorganic analysis usually
means examining materials to find
traces of other substances and uses
complex technology to break
mysterious substances down into
component elements, or types of
atoms.
Organic Compounds
The sole qualification for being an
organic compound is containing
carbon atoms. Carbon atoms on their
own are not considered organic
compounds; rather, usually the carbon
atoms are linked via covalent bonds to
elements such as oxygen, nitrogen or
hydrogen to form larger molecules,
hence the title "compound." All living
things are built from organic
compounds. Three classes of
compounds that do contain carbon but
aren’t considered organic are the
carbides, carbonates and cyanides.
These are formed through reactions of
heat and chemical bonding, either in a
lab or in nature.
Inorganic Compounds
Inorganic compounds, with the
exception of the three carbon-
containing inorganic compounds, are
those that contain no carbon. Because
the definition of a compound is that
two or more elements are combined,
inorganic compounds must contain at
least two noncarbon elements, usually
in definite proportion to one another.
The inorganic substance category
encompasses everything on earth and
in the known universe that does not
contain carbon, again with the
exception of carbides, carbonates and
cyanides.
Forensic Tools
Methods of forensic analysis involve
both organic and inorganic tools.
DNA analysis, for instance, is a
classic forensic tool that can pinpoint
a person’s presence at the scene of a
crime, establish paternity and help
free the wrongly accused. A common
example of inorganic analysis
involves decoding the marks left
behind by firearms discharging,
whether that is in the walls of a room
or on the casings of a bullet shell.
Toxicology reports are also useful,
indicating whether drugs were
involved in a crime, and can test for a
variety of substances.
THEORY OF FORENSIC
ANALYSIS
After a police officer or investigator
has collected evidence at a crime
scene, some evidence may be brought
to the crime lab for a forensic chemist
to analyze. The chemist follows a
specific process, based on the
scientific method, for analyzing
evidence. Samples collected from a
crime scene and brought to the lab for
analysis are called questioned samples
because the identities and origins of
those samples are unknown. In order to
draw conclusions about the identity or
origins of questioned samples, the
forensic chemist will need known
samples as a reference. A known
sample might be collected as part of
the evidence—for instance a hair
sample collected from a suspect.
Forensic analyses may be performed to
(1) identify a questioned sample or (2)
compare a questioned sample to a
known sample for the purpose of
determining the source or origin of the
sample (where it came from). The
results of such comparisons can link a
questioned sample and several known
samples either to a class of samples
with several possible origins
(classification) or to a single origin
(individualization). Thus, a forensic
chemist will analyze muchmore than
the questioned sample. A comparative
analysis may require the examination
of several known samples for each
questioned sample. A forensic analysis
follows the order of identification,
classification, and individualization, as
illustrated in Figure 5. The challenges
found during each phase of analysis
are different for each item of evidence.
Often, identification is straightforward
and obvious to the untrained eye (for
instance, hair); other times expertise
and sophisticated instrumentation are
required (for instance, drug analysis).
We will discuss each of these phases of
analysis in more detail in the sections
that follow.
Detecting forgeries and fingerprints
When fingerprints have been left for a
long time, they can be difficult to
detect and analyze. Nanotechnology
has led to a wave of new materials that
aim to visualize latent fingerprints, by
sticking well to the ridges and being
easy to detect. In a review in Synthetic
Materials, Dr. Adam Leśniewski, a
researcher at the Institute of Physical
Chemistry, Polish Academy of
Sciences, looks at the use of silica-
based materials that incorporate
nanoparticles and quantum dots,
among other substances, as more
effective methods to identify latent
fingerprints.
At the other end of the spectrum, an
ancient pigment could be just as
helpful. In a paper in Dyes and
Pigments, researchers from Curtin
University in Australia propose an
ancient dye that can has near-infrared
(NIR) luminescence. They
demonstrate that the pigment Egyptian
blue – the world’s oldest synthetic
pigment – enables forensic scientists to
detect otherwise invisible latent
fingerprints.
Chemical fingerprinting of fuels can
reveal fraud that causes significant
damage to engines and machinery.
Lubricating oil reduces friction and
keeps machines running smoothly, but
because it is so valuable it is subject to
fakery, with people deliberately
adulterating it to make money. Using a
fingerprinting analysis
technique described in the
journal Fuel, researchers
at Environment Canada characterized
new and used lube oils, showing how
the method could help identify
fraudulent products.
In other cases of fraud, paper analysis
can help forensic scientists understand
where a forged document originated.
In a new study in Journal of
Organometallic Chemistry,
researchers from Panjab University in
India explore the use of a technique
called chemometrics to characterize
and discriminate paper samples. They
characterized 24 paper brands by
matching peaks with cellulose and
fillers...
