OVERVIEW

A stock solution can be defined as a highly concentrated solution, mostly prepared as a 10x concentrated solution, which can be diluted to prepare a working solution. Stock solutions can also be used as a component to prepare complex solutions containing many ingredients. For example, a stock solution of EDTA (0.5M EDTA  solution) can be used to prepare many solutions which contain EDTA e.g., TAE, TBE, Tris-EDTA, Trypsin-EDTA etc.

Advantages:

• Since stock solutions are highly concentrated, their storage requires less space.
• It is also convenient to transport stock solutions due to their small volume.
• The concentration of various components of a working solution is more accurate when it is made from the stock solution rather than individual components from its original form.
• Stock solutions of biologically active substances (e.g., enzymes, inhibitors, DNA, RNA, etc.) are generally more stable in highly concentrated form.
• They are especially helpful in situations where you need a very minute amount of a component to prepare a complex solution.

Disadvantages:

• Since stock solutions are highly concentrated, often dissolving them requires more time and effort. Sometimes, heating of the solution is required to dissolve the substances completely.
• Long-term storage of stock solutions (especially salt solution, at low temperature) may lead to precipitation of solute.