L8: Chemical analysis of Trace Evidence

Question 1

whats the wavelength range?

Answer 1

200nm – 800nm wavelength range

Question 2

colour absorbance or transmittance by the fibre can be measured at?

Answer 2

400 - 800 nm

Question 3

is Microspectrophotometry destructive?

Answer 3

nope

Question 4

what does thin layer chromatography do?

Answer 4

separates the colour components to give a “fingerprint”

Question 5

is TLC destructive?

Answer 5

yes

Question 6

what does uv-vis spectrophotometry do?

Answer 6

Measures colour, often due to dyes or pigments, in a quantitative object
manner.
works on fibres, paints and inks

Question 7

is uv-vis spectrophotometry destructive?

Answer 7

no its normaly non destructive but when dyes extracted the analysis is carried out on the solution and this is destructive

Question 8

what does FTIR measure?

Answer 8

absorbance or radiation above ~800nm wavelength

Question 9

is FTIR destructive?

Answer 9

no

Question 10

FTIR looks at the characteristics of?

Answer 10

the vibration of chemical bonds in the material

Question 11

what does Raman Spectroscopy measure?

Answer 11

the gain or loss in energy of laser light scattered inelastically by molecules

Question 12

what does the spectrum in Raman Spectroscopy show?

Answer 12

difference in energy is characteristic of vibrations of the chemical bonds in the material

Question 13

Raman Spectroscopy is _______

Answer 13

non destructive

Question 14

what does FTIR identify?

Answer 14

functional groups from the pigment

Question 15

forensic vibrational spectroscopies characterise _______

Answer 15

the bulk chemical composition of a material

Question 16

start at

Answer 16

elemental analysis