Preliminary Practice

Poisons

Poisons are used more often than many people think, but not always maliciously. A diabetic can be poisoned by accident if there is too much sugar in their food, and anyone with a severe food allergy can be poisoned by their allergen. However, I am sad to say that people do use poison for malevolent purposes and it often comes into forensic investigations. In this lab we tested three samples per station for various poisons.

Poison n.- A substance that, when introduced into or absorbed by a living organism, causes death or injury, esp. one that kills by rapid action or chemical means.

Common Poisons

•   Severe allergic reactions

•   Overdosed prescription medicines

•   Poisonous plants

•   Household chemicals

•   Metal poisoning

Evidence of Poisoning (Pre/post- mortem)

•   Localized bruises

•   Vomit

•   Pupil Dilation

•   Bleeding from orifices

•   Excess drool/ foaming at mouth

Pre-Mortem symptoms

•   Increased heart rate

•   Skin burns or itches

Testing for Poisons (+ = Positive/- = Negative for poison)

Testing for	Sample 1	Sample 2	Sample 3
Metal Poisoning	Cr -, Pb +, Fe -	Cr -, Pb -, Fe +	Cr -, Pb -, Fe -
Sugar	Colorless> Blue-	Colorless> Blue-	Colorless> Blue-
Ammonia	pH 11/PHTH pink +	pH 8/PHTH colorless-	pH 7/PHTH colorless-
Aspirin	pH 2/ BTB yellow +	pH 8/ BTB blue-	pH 6/ BTB Green-
Cyanide	Colorless> Colorless-	Colorless> Blood Red +	Colorless> Colorless-
Iodine	Yellow>Yellow-	Pink>Pink-	Light Blue>Blue-black +