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competent cells: CaCl2 autoclave vs filter sterilisation - (Oct/08/2012 )

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SF_HK on Tue Oct 9 09:50:27 2012 said:


Lets say I make 1M Cacl2 (filter sterilise).

to make 200ml 0.1M Cacl2 (+15 glycerol)
- 20ml 1M CaCl2 (filter sterilised)
-30ml autoclaved 100% glycerol
-170ml autoclaved water

150ml water


Thank you. Yes I realised the calculation error when I was preparing the solutions.


Hi everyone. Im trying to prepare a 1M CaCl2 to make competent E.coli.


The chemicals available in my lab is anhydrous granular form, laboratory grade.


So my question is:


1. Does granular form of chemicals make accurate measurement of mw compared to powder form? 

2. Is laboratory grade cacl2 okay for making competent cells?


Appreciate any random opinions. Thanks

-Meg P. Anula-
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