Atomic Absorption Spectrophotometer (AAS) Clinical Applications – measure the concentration of metallic atoms (i.e., Ca, Mg, Pb, Zn, etc.) Principle 1.Measures the concentration of free metallic atoms, not molecules 2.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 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.