Ionic Composition within Fluid Compartments

• Though the total solute concentration within the different fluid compartments does nto differ in appreciable amounts, the solute concentrations of each particular solute, differs considerably between the compartments.

As can be seen, the major cation in the extracellular space is Sodium whilst in the intracellular space it is Potassium.
From the anion side, the major anion in the extracellular space is Chloride whilst in the intracellular space, the major anions are the Proteins and Phosphate ion.