Category: Stock solution
Preparation of 10 M Sodium Hydroxide (NaOH) Solution
Here we have described a procedure to prepare 10 M (or 10 N) sodium hydroxide (NaOH) solution. A 10 M NaOH solution can be prepared by dissolving 40 g of NaOH (Molecular Weight: 40.00) in water to a final volume of 100 ml. Since dissolution of NaOH in water is a highly exothermic reaction, extreme care must be taken while preparing the solution.
Preparation of 5X TBE Electrophoresis Buffer
TBE is a very common electrophoresis buffer for DNA agarose gel electrophoresis. It is prepared as a 5X stock solution that can be diluted to 1x or 0.5x working solution for DNA agarose gel electrophoresis. The 5X concentrated solution contains 0.445 M Tris borate and 0.01 M EDTA (pH 8.2 – 8.4).
A 5X stock solution is prepared by dissolving 54 g Tris base, 27.5 g Boric acid, and 20 ml of 0.5 M EDTA in water to a final volume of 1000 ml. The solution is sterilized by autoclaving and is stored at room temperature.
Stock Solution
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 (0.5 M EDTA solution) can be used to prepare many solutions which contain EDTA e.g., TAE, TBE, Tris-EDTA, Trypsin-EDTA etc.