Flame Test

Flame Colours

From video:

Alcohol - blue

Barium - yellow

Boron - green

Calcium - orange

Sodium - yellow

Copper - green

Potassium - lilac

Zinc - yellow

Found these on another website! Very detailed:) :

RedCarmine to Magenta: Lithium compounds. Masked by barium or sodium.Scarlet or Crimson: Strontium compounds. Masked by barium.Red: Rubidium (unfiltered flame)Yellow-Red: Calcium compounds. Masked by barium.Yellow

Gold: IronIntense Yellow: Sodium compounds, even in trace amounts. A yellow flame is not indicative of sodium unless it persists and is not intensified by addition of 1% NaCl to the dry compound.WhiteBright White: MagnesiumWhite-Green: ZincGreenEmerald: Copper compounds, other than halides. Thallium.Bright Green: BoronBlue-Green: Phosphates, when moistened with H2SO4 or B2O3.Faint Green: Antimony and NH4 compounds.Yellow-Green: Barium, manganese(II), molybdenum.BlueAzure: Lead, selenium, bismuth, cesium, copper(I), CuCl2 and other copper compounds moistened with hydrochloric acid, indium, lead.Light Blue: Arsenic and come of its compounds.Greenish Blue: CuBr2, antimonyPurple
Violet: Potassium compounds other than borates, phosphates, and silicates. Masked by sodium or lithium.Lilac to Purple-Red: Potassium, rubidium, and/or cesium in the presence of sodium when viewed through a blue glass.

Questions:

1) How and what is it used for in "crime scene investigations/forensic science"?

Flame analysis is based on the physical and chemical principle that atoms—after being heated by flame—return to their normal energy state by giving off the excess energy in the form of light. The frequencies of the light given off are characteristic for each element. Hence, it is used to identify different elements of substances. Since different elements produce different colours when heated with a flame, the colours produced can be compared to known standards and the presence of certain elements in the sample can be confirmed. Flame tests can also be used to determine the presence of metal elements in water by measuring the spectrum produced by the metals exposed to flame. The water is vaporized and then the emissions of the vaporized metals can be analyzed.

However, as useful as it is to forensic analysis, the flame test does not work on all elements. It cannot detect low concentrations of most ions and impurities can greatly affect the test results. For example, sodium is present in most compounds and can colour the flame.

2) If there are more than one trace metal present, is the flame test still a suitable technique to identify the trace metals?

It depends on the substances being used. As mentioned above, as many compounds are often contaminated with sodium, a cobalt blue glass can be used to

filter out the yellow flame and expand the ability to see violet and blue hues. For other trace metals however, the flame test is not a suitable technique to identify them as the flame would be seen as a mixture of many different colours.

Usage of cobalt glass:

3) Is flame test sufficient to identify the trace metal(s) present?

Not entirely. Many trace metals produce the same types of colours and some do not change the flame colour at all.

4) What is a "Mass Spectrometer"?

It is a machine that is used to determine chemical analytes in a chemical sample. Some are small enough to fit on a table, while others are so large that they fill entire rooms.

• A sample is loaded onto the MS instrument, and undergoes vaporisation

• The components of the sample are ionized by one of a variety of methods (e.g., by impacting them with an electron), which results in the formation of charged particles

• The ions are separated according to their mass-to-charge ratio in an analyzer by electromagnetic fields

• The ions are detected, usually by a quantitative method

• The ion signal is processed into mass spectra

(http://en.wikipedia.org/wiki/Mass_spectrometry)

Finger Printing

Ridges and pores activity
WOOD GLUE method

• Where are the pores found? Are they regularly spaced?
  • The pores are found between the ridges of the fingerprint and are quite regularly spaced throughout. The lines of the print are all quite regularly spaced, although at some parts, the lines merge or space out, hence forming different patterns.

Cyanoacrylate (Superglue) fuming method
Questions:
If the contrast of the white print against the black background is still too faint for a good detailed photograph to be captured, what could be done to enhance the fingerprint?
Powder dusting using a black substance such as lead could be used as the powder would get stuck between the ridges and pores of the print and allow it to be seen.

iodine fuming method
Questions:
What are the possible substances that may be used to render the prints more permanent?
Iodine can be mixed with solvents to create a liquid form of iodine and then sprayed onto the prints. This will allow the prints to last several hours.

For example,
1) Dissolve one gram of iodine in one liter of cyclohexane
2) Dissolve 5 grams of napthoflavone in 40 ml of methylene chloride (dichloramethane)
Why does the print disappear?
Iodine fumes evaporate very quickly.

Powder dusting method
Questions:
What is magnetic powder dusting and how does it work?
Magnetic powders dusting involves a fine magnetic powder being held by a magnetic applicator, which may then be gently moved across the fingerprint. The powder grains will get stuck in between the ridges of the fingerprint, enabling it to be seen. As no bristles touch the surface, this often damages the print less than other methods of developing the print.

Many other types of powders can be used, including chalk, charcoal and aluminium powder. The factors affecting which powder is used are adhesiveness, fineness, sensitivity, colour (so it can be seen on the surface) and flow.

Classification and identification of fingerprints
Introduction:
It is not clear which civilisation first utilised fingerprints as a form of identification. Evidence suggests that ancient Egyptians and Chinese create fingerprints on clay objects and official documents as a form of identification. There are however no known documents that describe how identification was conducted in ancient times.
Modern development of fingerprinting was mostly documented from 1858, when Sir William Herschel, British Adminstrator in District in India, required fingerprint and signatures on civil contracts. In 1892, Sir Francis Galton, a British Anthropologist and cousin to Charles Darwin, published the first book on fingerprints. He identified the individuality and uniqueness of fingerprints. In 1901, the first fingerprint bureau was eastablished in Scotland Yard. The system of classification was developed by Sir Edward Henry and is still the basis on which modern automated systems work to compare and identify fingerprints. 
The three basic fingerprint patterns are Whorl, Arch and Loop. There are more complex classification systems that further break down the pattern to plain arches or tented arches. Loops may be radial or ulnar. Whorls also have more detailed classifications.
According to the fingerprint database in the US:

• 60-65% are classified as loops
• 30 – 35% are classified as whorls
• 5% are classified as arches

Comparing 210 and America:

In 210's fingerprint database,

• 48% were classified as loops
• 45% were classified as whorls
• 3% were classified as arches

CSI - Website Mystery

18/7/11

Crime Scene Investigation
http://www.virtualmuseum.ca/Exhibitions/Myst/en/game/index.phtml

Physical Evidence:

• Robert Hughes, middle-aged male caucasian - not discreet, often flaunted wealth/philandering
• Break in, struggle
• Suspects -
  • Pretty blonde, went in at around 1:00 P.M. and left about an hour later in what appeared to be a very good mood (never seen before).
  • Feisty redhead, went in at around 4:00 P.M. and stormed out of the house fifteen minutes later (seen on several occasions) - Monica Fitzgerald, at home reading a book that night
    • Possible motive - Mr Hughes' affair
  • Pat the rat - Black Raven Bar that night (but no one remembers him there)
    • both times he committed crimes he stole from houses where he had worked as electrician
    • many fights in prison - could have become very violent and participated in murder struggle
• Mrs. Smith the next door neighbor reported seeing a strange man walking back and forth in front of the victim's house at around 10:15 P.M. on the night of the murder.
• Scene of Entry:
  • Tool Marks
    • Scratch marks
    • 2 types used to break lock - compression/sliding impression
    • Crowbar or something similar
  • Footwear
    • Mens' size 11 Doc Martin
    • Drags his feet
  • Paint Chips
  • Imagery and Computer Composite
    • sketches of the one man and two women
• Scene of Struggle:
  • Fingerprint
    • 30 different sets
    • one of which was from crystal vase used to hit victim across jaw
    • Patrick Murray "Pat the Rat" (convicted twice for break and enter, and theft, and was arrested once for assault, but not convicted he's now working for an electrical company called "Bright Lights "R" Us")
  • Hair strands
    • 5 types
    • Two of the hairs are quite long, and both are blond but of a different shade (one was bleached). The three other hair strands are relatively short, two brown and one a shade of red.
    • Red hair - female
  • Document Analysis
    • Woman in hate/love letter is very environmentally conscious. The paper she used comes from a shop that specializes in selling paper that is hand-made by people in Third world countries - "We are the World".
    • Written by redhead
  • Fibre Analysis
    • 0% wool and 50% polyester. They are dyed black and the weaving is very common for sweaters and such things
      
• Scene of Murder:
  • Blood
    • two puncture wounds, one to the neck, and the other to the heart
    • attacker lunged forward at the victim using a downward motion, must be at least as tall as the victim.5'9''
    • self-defence training?
  • Wound Analysis
    • 2 wounds, blade narrow, abt 4 inches, good quality switch blade
  • Blood analysis
    • one belongs to victim, one to woman
  • Time of Death
    • after he died, he was lying on his back for several hours
    • not moved after he was killed
    • 10.30pm last night

I guessed that the electrician was the murderer as

Field of Studies brought up:

(*)	Alcohol Analysis
(*)	Anthropology
(*)	Biology
(*)	Chemistry
(*)	Document Identification and Forgery
(*)	Entomology
(*)	Fingerprints
(*)	Firearms
(*)	Odontology
(*)	Pathology
(*)	Toxicology
(*)	Trace Evidence
(*)	References

Qualities of a good investigator:
Observant
Able to reason
Intelligent