Class Notes (836,102)
Canada (509,632)
FSC239Y5 (435)
Cahn (31)

FSC239 Jan 4 2011

3 Pages
Unlock Document

Forensic Science

FSC239 January 4 th Forensic Chemistry - application of analytical techniques to identify and compare evidence o determine composition o involves physical and chemical analyses of materials  ex. light absorption and emission - forensic labs perform analyses on wide range of materials Chemical Analyses Organic Compounds - drugs – alcohol, mj, herion - synthetic fibers - petroleum products – gas - paint binders - high grade explosives - organic compounds contain carbon - commonly bonded to H, O, Ni, S, P, Cl - nature of bonds between elements o compounds can be characterized by absorption of light - spectrophotometry: method for identifying substances based on selective absorbance of different wavelengths of light o requires material to be pure  often beyond control of FS Chromatography - separating components of a mixture based on differing attractions to a stationary phase while propelled by a moving phase - molecules having greater affinity (more soluble) for moving phase pushed along a faster rate – causes separation - can be thought of as a race btwn chemical compounds o at start, all mixed together o as race progresses, components separate o at completion, all participants separate, each cross finish line at different time - after separated, compounds are ionized and recorded on a graph - gas chromatography o liquid stationary phase and moving gas phase o gas flows through a column containing thin film of liquid  on walls – capillary, on smaller granular particles – packed o sample injected as liquid and vaporized o chromatogram generated  electrical signal given off by emerging component when ionized by detector  recorder response graphed against time  time required for a component to emerge from the column is known as the retention time o useful identifying feature but it does NOT produce specific identification o largely used to separate compounds HPLC and TLC - HPLC: high performance liquid chromatography o solid particle stationary phase and moving liquid phase – liquid pumped through column - entire process takes place at room temperature o no need to vaporize sample o useable for temperature-sensitive materials ex. explosives, LSD - TLC: solid stationary phase (coated plate) and liquid mobile phase - liquid rises up plate by
More Less

Related notes for FSC239Y5

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.