Abstract
Atomic-absorption spectrophotometry is applied in the analysis of biological membrane materials for micromolar levels of the physiologically important cations, Na, K, Mg, and Ca. Instrumental parameters and chemical interferences are investigated and a method for the measurement of all four cations in a single sample of ashed membrane material is formulated, tested, and applied. Results are highly satisfactory, and demonstrate that atomic-absorption spectrophotometry affords biologists a powerful and sensitive tool for the study of the important rôle played by inorganic ions in living systems.