POISON_FORENSIC CHEMISTRY

Gaseous Poisons

Carbon dioxide; Carbon monoxide; nitrogen (Nitrous oxide, Nitric acid and Nitrogen dioxide); war gases.

Metallic Poisons and Salts

(These chemicals are protoplasmic irritants, but their chief action is the deleterious effect produced after absorption into the system.)

• Mercury; Lead; Gold; Platinum; Nickel; Chromium; Tin;

Volatile Poisons

(Volatile liquids or easily sublimated solids many of which are irritants; their chief action occurs after absorption)

Alkaloidal Poisons

(These substances are toxic principles of plants like opium and marijuana which have a characteristic action on some parts of the central nervous system; they are a well-defined group)

Miscellaneous Poisons

(Associated with botulism; food poisoning; mushroom poisoning; snake venom poisoning

• 1. Food Poisoning: Toxic substances in the food; Abnormal hypersensitivity to normal constituents of food.

• 2. Poisonous Plants.

• 3. Poisonous Animals and Their Poisons: Arachnids; Centipedes; Insects; Caterpillars; Vertebrates.

• 4. Biological Products.

CARBON MONOXIDE

• CARBONIC OXIDE GAS, CO "SILENTKILLER”

• is formed from the incomplete combustion of carbon fuel. The fatal carbon monoxide poisoning usually involves burning of wood, oil, coal, kerosene and charcoal used in heating or cooking, or gasoline engines in cars.

Kunkel's Test

The suspected blood, diluted with 4 volume of water is mixed with three times its volume of 1% tannic acid solution and shaken well. If carbon monoxide is present, a crimson-red coagulum which retains its color for several months will develop. Normal blood forms a coagulum, which is, at first red, and becomes brown in the course of one to two hours and then gray up to 24 to 48 hours.

Potassium Ferrocyanide Test

15 cc. of blood is mixed with equal amounts of 20% potassium ferrocyanide solution and 2 cc. of dilute acetic acid and shaken gently. A dark brown coagulum will be formed if the blood is normal.

HYDROGEN SULFIDE

• SULPHURETTED HYDROGEN, H2S

is formed during a decomposition process of organic substances containing sulphur. It is found in large quantities in a sewer, septic tanks, drainage pipes, and deep wells. It may be a by-product in some industries, like tannery, rayon factories, petroleum refineries, sulfur dye work, etc. It is a colorless, transparent gas, sweetish taste and emiting an odor similar to a rotten egg. The gas is soluble in water to form carbonic acid and it burns in the air with a pale blue flame.

HYDROGEN CYANIDE

is one of the most toxic and rapid acting gases. It is formed by addition of acid to potassium or sodium salt of cyanide. It is naturally found in leaves of cherry-laurel, in bitter almond, in kernels of common cherry, plum, peaches, in ordinary bamboo shoots, and in certain oil seed and beans. These plants contain a crystalline glucoside known as amygdalin which, in the presence of water and natural enzyme, called emulsin, is readily decomposed into hydrocyanic acid, glucose and benzaldehyde.

SULFUR DIOXIDE

is a colorless gas, which is heavier than air and with pungent odor.

• It is employed as a disinfectant, as a bleaching agent, a powerful reducing agent, and found usually in eruption of volcanoes. The gas produces irritation of the respiratory passage, thus causes sneezing, coughing, spasm of the glottis and suffocation.