OVERVIEW

A 0.5M stock solution of Rubidium chloride (RbCl, Molecular weight = 120.92) can be prepared by dissolving 6.046 g RbCl in deionized water to a final volume of 100 ml.

REQUIREMENTS

Reagents and solutions
Rubidium chloride (RbCl, Molecular weight = 120.92)
Double distilled water 

Equipment and disposables
Measuring cylinder 
Conical flask / Beaker 
Magnetic stirrer 

PREPARATION

Step 1: To prepare, 100 ml of 0.5 M Rubidium chloride (RbCl) solution, weighs 6.04 g RbCl (Molecular weight = 120.92) and transfer it to a 250 ml beaker/conical flask. Add 80 ml deionized/distilled water and mix it manually/using a magnetic stirrer until all Rubidium chloride dissolves completely.

Note
Do not dissolve in 100 ml water. In most cases, the volume is increased when a large amount of solute dissolves in solvent. It is preferred to dissolve the solute in a small volume of solvent (e.g., 80% of the final volume). After the solute is completely dissolved and pH is adjusted (if required), make up the correct volume with the solvent. 

Step 2: Adjust the volume to 100 ml with deionized/distilled water.

Step 3: Transfer the solution to an autoclavable bottle and sterilize the solution by autoclaving (20 minutes at 15 lb/sq.in. (psi), 121-124°C on liquid cycle).

Note
One can sterilize the solution by filtering through a 0.22 μ filter unit. Filter sterilization removes all suspended particles with size more than 0.22 μ which includes most bacteria and their spores but not mycoplasma. In addition, it does not inactivate enzymes (e.g., DNases). In contrast, autoclaving inactivates most enzymes except some (e.g., RNases) and kills most microorganisms including mycoplasma.

Storage 

Solution can be stored at room temperature.

Applications 

Competent cell preparation