Saltkoncentration

Saltkoncentration refers to the amount of dissolved salts in a solvent, most commonly water. It is defined by the concentration of charged ions—such as Na+, K+, Ca2+, Cl−, and SO4^2−—present in the solution. For practical purposes, saltkoncentration can be expressed with several units: molarity (moles of salt per liter of solution), molality (moles per kilogram of solvent), mass percentage (grams of salt per 100 g of solution), or parts per thousand (per mille, ‰). In marine and environmental contexts, salinity is often reported in practical salinity units (PSU), which approximate the dissolved salt content of seawater.

Typical reference values include physiological saline at about 0.9% w/v NaCl, used to balance body fluids, and seawater at roughly 3.5% w/w total dissolved salts (about 35 g of salt per kilogram of seawater). Since salt in solution consists of multiple ions, the overall concentration can be expressed as osmolarity or osmolarity, taking into account the van’t Hoff factor (for NaCl, i ≈ 2). This determines osmotic pressure and influences freezing point and boiling point.

Measurement methods include conductivity to estimate ionic strength, refractometry in some settings, ion chromatography for individual ions, and gravimetric or titrimetric techniques for total dissolved solids.

Applications span biology, medicine, food science, water treatment, and desalination. Maintaining appropriate saltkoncentration is essential for cell function, flavor and texture in foods, and the efficiency of desalination and purification processes.