- Weigh out 54 g CaCl2?H2O and dissolve in 170 ml of distilled water.
- Make up volume to 200 ml with distilled water.
- Sterilize the solution by passage through a 0.22-micron filter.
<STORAGE> Store in 1 ml aliquots at -20 C.
<USAGE> When preparing competent cells, thaw an aliquot and dilute it to 100ml with distilled water. Sterilize the solution by filtration through a Nalgene filter (0.45 micron), and chill it to 0 C before use.