In analytical chemistry, a standard solution (titrant or titrator) is a solution containing an accurately known concentration. Standard solutions are generally prepared by dissolving a solute of known mass into a solvent to a precise volume, or by diluting a solution of known concentration with more solvent. A standard solution ideally has a high degree of purity and is stable enough that the concentration can be accurately measured after a long shelf time.
Making a standard solution requires great attention to detail to avoid introducing any risk of contamination that could diminish the accuracy of the concentration. For this reason, glassware with a high degree of precision such as a volumetric flask, volumetric pipette, micropipettes, and automatic pipettes are used in the preparation steps. The solvent used must also be pure and readily able to dissolve the solute into a homogenous solution.