Forensic
Toxicology Quiz Crafted
by-
Dr. Mamta Pal
Former Associate Professor
Department of Forensic Science
School of Basic & Applied Sciences, Galgotias University
Introduction about Toxicology
Poisons are substances which causes harm to an organism when
absorbed, inhaled or ingested in sufficient quantity. A toxin is a poisonous
substance that is produced within the living cells. Toxicology is the science
that involves the study of chemical substances and their adverse effects on living
organisms.
Here’s the short interview of Quiz maker
Can you
enlighten us how forensic toxicology is different from toxicology?
Toxicology is the discipline, which deals with the study of
substances which can exert adverse effects on the biological system and it
encompasses their interaction, symptoms, diagnosis and treatments in living
organism. Whereas, in conjunction to the
toxicology, Forensic toxicology deals with the analysis of toxic substances by
various methods and techniques to aid the legal investigation to know the cause
of poisoning, which is referred as the medico-legal aspect of poisoning.
Further, forensic toxicology utilizes the other disciplines also such as
pharmacology, clinical toxicology and analytical chemistry for the examination
of nature and cause of toxicity.
How toxicological analysis is performed?
Toxicological analysis is performed by
presumptive colour test followed by crystal test and finally confirmed by
analytical instrumental technique and the sample required for such analysis
depends upon the type of case, for example, whether the toxicity has reported
in live person or it is the case of deceased person or whether a drug or poison
has recovered in pure form or has seized in crude form. Thus, if the cause of
toxicity is to be established in live person, the sample required would be the blood, urine, vomit content, nails, hairs etc. and if the cause of
toxicity is to be determined in a deceased, the analysis will be carried out in
bile juice, stomach content, visceral organs such as liver, heart, brain tissue
etc. depending on the nature of the poison. Therefore, from the toxicological
examination point of view, collection and preservation of biological samples
are also of the great importance.
How drugs are identified?
Identification of drug, whether it is found in pure form or in
mixture or seized in crude form or recovered from biological exhibits (in case
of poisoning in live person or deceased), requires chemicals, reagents, precise
methods for sampling to perform presumptive tests and crystal tests followed by
instrumental analysis by employing sophisticated techniques such as
colorimetry, spectrophotometry, chromatography etc. depending upon the type of
poison or drug to be analysed. For e.g., if it is the case of metallic poisons
analytical techniques used are AAS, MS, ICP etc. whereas, in case of volatile
poisons, GC is used and examination of non-volatile drugs is carryout by LC.
Are there any techniques which can give rapid results?
There are various hyphenated techniques which are employed for the
accurate and rapid identification of poisons. When one analytical technique is
coupled with the another analytical technique, it is known as hyphenated
technique like coupling of chromatographic technique with spectrophotometric
technique such as hyphenation of liquid chromatography with mass
spectrophotometry is known as LC-MS, hyphenation of gas chromatography with
mass spectrophotometry is known as GC-MS and ICP-MS is the example of coupling
of emission spectroscopy with mass spectrophotometry etc., which make the
analysis more advanced. Where, LC/GC are used to separate the pure analyte from
a mixture and MS is used to characterize the purified component and hence,
provide rapid, accurate and reproducible results.
Now let’s have a look at the answers of the Quiz:
Ques 1.
Corrosive poisons are the poisons which
a) Affect
CNS
b) Cause
paralysis of muscles
c) Cause
inflammation at the site of contact
d) Multiple
organ failure
Answer. (c) cause inflammation at the site of
contact
Explanation: Ingestion of corrosive
substances may cause severe injuries to the gastrointestinal tract and even
death. Corrosive substances such as acids (hydrochloric, acetic,
sulfuric, lactic, oxalic, carbolic), alkalis (sodium and potassium, soaps, detergents),
heavy metal salts (sublimate), formalin, iodine tincture and many other
chemical substances, cause oral intoxication when ingested.
Ques 2. Which one of the following is
corrosive acid?
a) NaOH
b) KOH
c) Na2CO3
d) HCL
Answer. (d) HCL
Explanation: HCL is the aqueous (water-based) solution
of hydrogen chloride gas. It is a strong acid and the major
component of gastric acid. It is widely used in industries. It should be
handled with appropriate safety precautions because it is a highly corrosive liquid.
Ques 3. Chloroform in the biological
exhibit is identified by?
a) TLC
b) GC
c) HPLC
d) AAS
Answer. (b) GC
Explanation: Chloroform is a heavy
volatile liquid which can be identified using gas chromatography. GC is a
separation technique utilized to analyze volatile compounds in gas phase. It
was discovered by Mikhail SemenovichTsvett in 1900s.
Ques 4. Which one of the following is
known as oil of vitriol?
a) HCL
b) H2SO4
c) HNO3
d) Linseed
oil
Answer. (b) H2SO2
Explanation: Oil of vitriol or H2SO2
is a hygroscopic, syrupy corrosive liquid. It is called oil of vitriol because
earlier it was prepared by heating green vitriol (iron II sulphate, FeSO4)
in an iron container.
Ques 5. Following method is used for
the extraction of metallic poisons
a) Dry
ash method
b) Wet
digestion method
c) Both
dry ash and wet digestion method
d) None
Answer. (c) Both dry ash and wet digestion method
Explanation: The residue left after
performing dry ash method is tested for metallic poisons such as copper, zinc,
barium, bismuth, etc. Wet digestion method is also known as acid mineralization
which involves chemical decomposition of sample matrices using oxidizing and
dehydrating properties of concentrated minerals acids into aqueous solutions.
Ques 6.Reinsch test is used for?
a) Mercury
b) Arsenic
c) Both
arsenic and mercury
d) None
Answer. (c) Both arsenic and mercury
Explanation: Among heavy metals,
arsenic is the second most common cause of poisoning. Contrarily, mercury
poisoning is relatively uncommon but still poses threat because of its extreme
toxicity. Reinsch test can be used as a screening tool for both arsenic and
mercury.
Ques 7.
Stricture formation is more common in the following case?
a) Neutral
poisons
b) Alkali
poisoning
c) Acid
poisoning
d) None
of the above
Answer. (b) Alkali poisoning
Explanation: Caustic ingestion is a
serious health issue due to the ready availability of caustic agents.
Substances with high pH are very corrosive and can cause severe injury to the
gastrointestinal tract. It affects esophagus and stomach most seriously and may
lead to chronic complications like stricture formation, gastric outlet
obstruction, and malignant transformation.
Ques 8. Metallic species can be
identified by?
a) MS
b) ICP
c) AAS
d) All
of the above
Answer. (d) All of the above
Explanation: MS measures
mass-to-charge ratio of molecules present in a sample and generates metal
specific isotopic spectra, ICP uses emission spectra to identify and quantify
an aerosol sample and AAS utilizes element specific light absorption to
determine the concentration of a metal in a solution.
Ques 9. Diamond dust is an example of?
a) Inorganic
poisons
b) Organic
poisons
c) Mechanical
poisons
d) Both
a & b
Answer. (c) Mechanical poisons
Explanation: Diamond dust does not act
as a poison as it does not get dissolved in blood but it is a mechanical poison
as it acts mechanically by causing irritation to the gastrointestinal tract.
Ques 10. Neurotic poisons are the poison
which affects?
a) CNS
b) Peripheral
of brain
c) Spinal
of brain
d) All
of the above
Answer. (d) All of the above
Explanation: Neurotic poisons affects
different parts of central nervous system. Cerebral poisons such as alcohol, opium,
barbiturates, etc. are CNS depressing agents, Strychnine is a spinal poison
which is an active constituent derived from strychnosnux vomica and Curare is a
peripheral poison which affects the peripheral nerves of the brain.
Ques 11. Curare is a
a) Peripheral
poison
b) Cerebral
poison
c) Spinal
poison
d) Cardiac
poison
Answer. (a) Peripheral poison
Explanation: Curare is a neuromuscular
blocking agent as it produces flaccidity in muscles. Various tropical American
plants are its source.
Ques 12. Strychnosnux vomica is a?
a) Cardiac
poison
b) Spinal
poison
c) Cerebral
poison
d) Peripheral
poison
Answer. (b) Spinal poison
Explanation :The dried seeds of
nux-vomica are called Kuchla which contains 2.6%-3% total alkaloids, out of
which 1.25%–1.5% is strychnine, 1.7% is brucine and the rest are vomicine and
igasurine. It inhibits the inhibitory action of spinal interneurons on the
muscles and leads to twitching and muscle spasms.
Ques 13. Following is a cardiac poison
a) Ethyl
alcohol
b) Strychnine
c) Dhatura
d) Digitalis
Answer. (d) Digitalis
Explanation: Digitalis is also known
as foxglove. Its leaves are used to extract digoxin, a cardiac glycoside which
inhibits Na+/K+ ATPase pump in cardiac muscles indirectly increasing the
calcium levels, allowing the heart to work more efficiently. But when given in
large amount and more frequently it becomes toxic leading to sickness,
giddiness, slow pulse, etc. and even death.
Ques 14. Following is not an example of
asphyxiant
a) CO
b) O2
c) CO2
d) CH3
Answer. (b) O2
Explanation: Oxygen is a tasteless,
odorless and colorless gas which supports life. It is non-combustible but
supports burning of combustible substances.
Ques 15. Following are the category of
agricultural poisons
a)
Organochloro insecticide
b)
Organophosphorous insecticides
c)
Carbamates
d)
All of the above
Answer. (d) All of the above
Explanation: Agricultural
chemicals are pesticides that includes insecticides which is divides into four
main categories, which are: organophosphates, carbamates, chlorinated
hydrocarbons and insecticides. Organophosphates and carbamates exaggerate the
normal functions of the parasympathetic system. Chlorinated hydrocarbons used
as insecticides stimulates the central nervous system. Insecticides are derived
from plants and have rapid knockdown effect for insects.
Ques 16. Which of
the following are used for cattle poisoning?
a) Abrusprecatorius
b) Calotropis
c) None
of the above
d) Both
a & b
Answer. (d) Both a & b
Explanation: Abrusprecatorius is
commonly known as Rosary pea, it produces poisonous effect when injected
subcutaneously. Calotropis is known by local names such as ‘Madar’ and ‘Akdo’
and is found throughout India. It is used as suicide, homicide, infanticide and
as cattle and arrow poison. In India, they are utilized for the malicious
destruction of cattle.
Ques 17. Anions are isolated from
viscera by?
a) Acid
steam distillation method
b) Dialysis
c) Alkali
steam distillation
d) Both
a & b
Answer. (b) Dialysis
Explanation: Toxic anions includes
chlorate, borate, fluoride, iodide, etc. In some cases, anions are used as
active species such as borate, oxalate, these anions are to be especially
isolated in case of biological materials. Anions are sometimes found in
combination with a cation, after which the organic matrix is destroyed with
metals. Other anions ca be separated from the matrix by dialysis.
Ques 18. Volatile organic poisons are
isolated by?
a) Alkali
steam distillation
b) Dialysis
c) Acid
steam distillation
d) None
of the above
Answer. (c) Acid steam distillation
Explanation: Acid steam distillation
method is utilized for compounds with a relatively high vapor pressure, which
are immiscible in cold water. This method has both extraction and separation
function as it can separate target volatile compound from non-volatile
compounds.
Ques 19. Following is the example of
carbamates insecticide
a)
Baygon
b)
Carbaryl
c)
Both
d)
None of the above
Answer. (c) Both
Explanation: Carbamate
insecticides includes baygon, carbaryl, seven, etc. they act by inhibiting
acetylcholinesterase, which is an enzyme that degrades acetylcholine. Carbamate
are widely utilized as they are more degradable than organophosphates and have
lower dermal toxicity.
Ques 20.
Non-volatile organic drugs can be examined by following analytical technique
a)
AAS
b)
MS
c)
HPLC
d)
SDS-PAGE
Answer. (c) HPLC
Explanation: HPLC
provide direct separations of non-volatile compounds using liquid mobile phase
and solid stationary phase. The different substances in the sample injected
distribute themselves according to their affinity with the two phases.