AA spectrometer

• atomic absorption spectrophotometry

  A) light source

  B) chopper

  C) sample (atoms)

  D) fuel

  E) oxidant

  F) sample

  G) aspirating air

  H) drain

  I) mixing baffles

  J) burner head

  K) monochromator

  L) PM tube

  M) readout

  
• atomic absorption spectrophotometry

  • light source - filled with argon gas (inert gas) and the element being tested
• • Chopper - creates a strobe effect from the excitation spectra; no longer a steady stream of light hitting sample; “pulse” of light; this strobe effect helps photomultiplier to distinguish emitted light from excitation/incident light 
• function of chopper in atomic absorption spectrophotometry: way for PM tube to distinguish emitted light from incident light
• atomic absorption spectrophotometry

  • Burner head - analogous to cuvette 
• • Venturi effect - causing fluid to be drawn up into a tube by creating negative pressure; done to draw up sample in atomic absorption spectrophotometer
• atomic absorption spectrophotometry

  • Aspirating air also atomizes the sample 
• atomic absorption spectrophotometry

  • Fuel injected to ignite flame 
• atomic absorption spectrophotometer

  • Oxidant injected; acts upon atom we are trying to quantify
• The mixing baffles in atomic absorption spectrophotometer mixes aspirating air, oxidant, fuel, and sample by creating turbulence; creates homogenous air that enters burner head
• Drain in atomic absorption spectrophotometer is needed as some of the mixture in the mixing baffles will stick and go to the bottom
• A homogenous mixture hits the burner head; contains atom we are trying to quantify, oxidant, fuel, and air; fuel will burn; mixture of heat and oxidant excites ion we are trying to quantify