Spectroscopic techniques Flashcards
What is the difference between UV, infrared and microwave waves?
UV light excites electrons but does not have enough energy to pass through the matter. Infrared causes the atom bonds to vibrate. Microwave causes the molecules to rotate and spin
What does UV/visible spectrophotometry measure? What is its purpose?
The intensity of light that passes through a sample as some quantity if absorbed by the atoms to excite the electrons. Determines exact colour of a substance and characterises organic substances
What is the difference between transmission and absorption spectrum?
Transmission spectrum is the graph of wavelength versus light intensity while absorption spectrum is the graph of wavelength versus light absorbed
What is involved in infrared spectroscopy?
The sample is combined with potassium bromide and exposed to light of all infrared wavelengths to produce a unique IR spectrum
What is involved in Raman spectroscopy?
Measures the difference in energy of absorbed photons and the scattered photons, depending on the vibrations of the molecular bonds
What is electron impact mass spectrometry?
Type of mass spectrometry that involves bombarding the sample with a stream of electrons to induce ionisation
What is chemical ionization mass spectrometry?
Type of mass spectrometry that involves using small molecules to ionize the compound
What is laser desorption mass spectrometry?
Type of mass spectrometry that involves using a laser to remove electrons from the surface of a material, ionizing it
What are the three primary methods of separating cations?
Magnetic sector, quadrupole and ion trap
What is atomic absorption in atomic spectroscopy?
Using a lamp which emits specific wavelengths to measure the amount of light absorbed by the sample. The amount of the element present is proportional to the quantity
What is emission spectroscopy in atomic spectroscopy?
The measurement of the photons emitted as excited electrons return to ground level
