UV/Vis atomic spectroscopy (AES and AAS) UPDATED ACTUAL
Questions and CORRECT Answers
Atomic spectroscopy used to determine both bulk (% w/w) and trace (<ppm) element composition
Atomic emission spectroscopy A technique in which the emission of light by thermally excited atoms or ions
in a flame, furnace, or plasma is used to measure concentration
-shows intensity of light as a function of wavelength (proportional to
concentration)
Analysis process choose a relatively strong emission lines for each element that does not
overlap with strong lines from other elements in the sample (<1 nm different)
-signals proportionat to concentration so internal standards can be used
internal standard accounts for:
-variability in the sample introduction
-variability in atomization temperature
AES spectrometer 1. Sample: must be acidified
2. peristaltic pump: draws sample at several mL/min
3. nebulizer: converts liquid sample into fine mist
4. spray chamber: mist droplets to torch
5. torch: location of atomization
Inductively coupled plasma (ICP) -ionization of argon (Ar) is initiated with a spark
-magnetic flux from induction coils accelerates argon ions
Microwave induced plasma (MP) -ionization of nitrogen (N2) is initated with a spark
-microwave radiation causes electrons and ions to oscillate
Questions and CORRECT Answers
Atomic spectroscopy used to determine both bulk (% w/w) and trace (<ppm) element composition
Atomic emission spectroscopy A technique in which the emission of light by thermally excited atoms or ions
in a flame, furnace, or plasma is used to measure concentration
-shows intensity of light as a function of wavelength (proportional to
concentration)
Analysis process choose a relatively strong emission lines for each element that does not
overlap with strong lines from other elements in the sample (<1 nm different)
-signals proportionat to concentration so internal standards can be used
internal standard accounts for:
-variability in the sample introduction
-variability in atomization temperature
AES spectrometer 1. Sample: must be acidified
2. peristaltic pump: draws sample at several mL/min
3. nebulizer: converts liquid sample into fine mist
4. spray chamber: mist droplets to torch
5. torch: location of atomization
Inductively coupled plasma (ICP) -ionization of argon (Ar) is initiated with a spark
-magnetic flux from induction coils accelerates argon ions
Microwave induced plasma (MP) -ionization of nitrogen (N2) is initated with a spark
-microwave radiation causes electrons and ions to oscillate
