MLAB 2401: Clinical ChemistryKeri Brophy-Martinez

Atomic Absorption Spectrophotometry

Atomic Absorption Spectrophotometer

Atomic Absorption Spectrophotometer (AAS)

• Clinical Applications– measure the concentration of metallic atoms (i.e., Ca, Mg, Pb,

Zn, etc.)

• Principle1. Measures the concentration of free metallic atoms, not

molecules2. An acetylene (or occasionally argon) powered flame dissociates

molecules isolating the metallic atoms.3. A beam of monochromatic light (produced by a special hollow

cathode lamp) passes through the top of the flame.4. The metallic atoms absorb the light proportionally to their

concentration.

Atomic Absorption Spectrophotometer

Atomic Absorption

Atomic Absorption Spectrophotometer

• Specimens– Usually diluted with DI water• Serum• Urine• Hemolysate• Hair

Atomic Absorption Spectrophotometer

• Interferences– occur for variety of reasons, usually can be prevented

or limited.

• Three types– Chemical

• Chemical interference is when other atoms present absorb light.

– Physical• Flame temperature/ sample aspiration

– Ionic• Some elements would rather ionize than dissociate

in their ground state

References

• Bishop, M., Fody, E., & Schoeff, l. (2010). Clinical Chemistry: Techniques, principles, Correlations. Baltimore: Wolters Kluwer Lippincott Williams & Wilkins.

• Sunheimer, R., & Graves, L. (2010). Clinical Laboratory Chemistry. Upper Saddle River: Pearson .