80 likes | 224 Views
MLAB 2401: Clinical Chemistry Keri 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.) Principle
E N D
MLAB 2401: Clinical ChemistryKeri Brophy-Martinez Atomic Absorption Spectrophotometry
Atomic Absorption Spectrophotometer (AAS) • Clinical Applications • measure the concentration of metallic atoms (i.e., Ca, Mg, Pb, Zn, etc.) • Principle • Measures the concentration of free metallic atoms, not molecules • An acetylene (or occasionally argon) powered flame dissociates molecules isolating the metallic atoms. • A beam of monochromatic light (produced by a special hollow cathode lamp) passes through the top of the flame. • 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 .