Poison Test Activity (Sunday December 4 2011)

During an actual murder case, some criminals might use poison to murder the victims. Due to this, forensic scientists should be prepared to analyze beverages, food. etc. for any type of poisoning. 

When one thinks of being "poisoned" they usually imagine the cause to be rat poison, or chlorine, etc. However, there are also different types of poisons. For example, a person may be allergic to peanuts. If the person ate the food with peanuts included (given to them by the murderer) then the person would be killed without the need of any heavy chemicals. 

before the actual activity, we did some research on poison:

1. what is the definition of poison?

    A substance which causes a slow or quick death, or an injury when when that substance is introduced to a living organism. 

2. list common poison sources:

1. inedible home products 

2. home cleaning utensils 

3. pest control devices

4. food poisoning- bacteria in foods

5. certain plants

6. lead paint

7. incorrectly used medicine

8. poisonous insects

3. how do crime labs handle poison cases?

They use a variety of chemicals at their disposal in order to determine whether or not a victim was poisoned:

1. Ammonia poision- pH above 7 (basic), odor, and if "phth"(phenolphthalein) is purple in solution

2. Cyanide-turns dark red when a Fe (iron) cation is added. 

3. Iodine- turns black when starch is added 

4. Aspirin-pH is below 7 (acidic): "btb" (bromothymol blue) is yellow

4. what are signs of poisoning?

1. foaming/drooling at mouth

2. change in heart rate

3. skin irritation

4. bleeding at mouth, eyes, etc.

5. enlarged/dilated pupils

For this Activity, we had to determine if 3 types of 6 different liquids contained metal, sugar, household ammonia, aspirin, cyanide, or iodine poisoning. We determined whether or not the liquids were poisoned based on the changes when the reagent or chemical was added. 

here are the results:
1. Metal Poison Test:

metal test

   a.Cr (chromium)- orange when acidified
       1 negative
       2negative
       3 negative
   b.Pb (lead)- yellow precipitate when KI is added
       1 negative
       2positive
       3negative
   c.Fe (iron)- red when KSCN (potassium thiocyanate)
       1 negative

sugar test

       2 positive
       3negative
2: Sugar Poison Test:
    1.negative
    2. negative
    3. negative
3: Household Ammonia Test:
    a.Odor:
       1.  positive

ammonia test

       2.negative
       3.negative
 b. pH
      1. positive (10)
      2.positive (9)
      3. positive (10)
  c.purple in solution
       1 positive
       2negative
       3 negative
4: Aspirin Poison Test:

aspirin test

    a.pH below 7
        1 positive
        2.negative
        3negative
    b. BTB is yellow
       1positive
       2negative
       3negative
5. Cyanide Test:

cyanide test

  1. negative
  2. positive!!
  3. negative
6. Iodine Test:
  1. negative
  2. negative
  3. negative, 

iodine test