LimsPulse
Spectroscopy

Atomic Absorption Spectrophotometer (AAS)

Measures one metal at a time by how much light of that element's own wavelength is absorbed by free atoms in a flame or graphite furnace. Simple, robust and still widely used for metals in pharma QC.

  • Pharmaceutical
  • Food & beverage
  • Environmental
  • Mining & metallurgy
  • Agriculture
  • Clinical
Photo of a Atomic Absorption Spectrophotometer (AAS)
Photo: Talos (German Wikipedia), CC BY-SA 3.0 (cropped), via Wikimedia Commons
Follow your site SOP
This is a typical operating sequence for learning. Your instrument model and approved SOP take precedence.
STAGE 1

Before you start

  1. 1Check the calibration status label and the instrument log book.
  2. 2Check acetylene cylinder pressure; replace the cylinder when the contents gauge falls below the level in your SOP so acetone is not carried into the burner.
  3. 3Switch on the exhaust above the burner and confirm it is working.
  4. 4Fit and select the lamp for the element and allow it to warm up (often 10–30 minutes).
  • Never light the flame without the exhaust running and the burner head fitted correctly.
STAGE 2

Set-up and optimisation

  1. 1Set the wavelength, slit width and lamp current from the method.
  2. 2Ignite the flame following the instrument sequence (air first, then acetylene) and let it stabilise.
  3. 3Aspirate a mid-range standard and optimise burner height, alignment and fuel flow for maximum absorbance.
  4. 4Aspirate blank and zero the instrument.
  • Keep the drain trap filled with liquid; an empty trap can let flame gases escape and cause flashback.
STAGE 3

Measurement

  1. 1Run the calibration blank and standards (typically 3–5 levels) and check the correlation coefficient.
  2. 2Run a check standard to confirm the calibration, then the samples.
  3. 3Aspirate blank or water between samples to rinse the nebuliser.
  4. 4Re-run a check standard at the frequency in the method (e.g. every 10 samples) and at the end.
  • Dilute samples that read above the top standard; do not extrapolate the curve.
STAGE 4

Shutdown

  1. 1Aspirate purified water for a few minutes to clean the nebuliser and burner.
  2. 2Extinguish the flame using the instrument shutdown sequence.
  3. 3Close the acetylene cylinder valve and bleed the line if required by the SOP.
  4. 4Switch off lamps and record usage in the log book.
In LimsPulse · Calibration Management

Keep every AAS in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how