
competent cells: CaCl2 autoclave vs filter sterilisation
#1
Posted 08 October 2012 - 12:21 AM
Thank you
#2
Posted 08 October 2012 - 04:34 AM
#3
Posted 08 October 2012 - 06:51 AM
I just simply prepared 0.1M CaCl2 by dissolving 3.67g CaCl2 (dihydrate, FW 147.02) in 250ml water.
#4
Posted 08 October 2012 - 10:01 AM
I just simply prepared 0.1M CaCl2 by dissolving 3.67g CaCl2 (dihydrate, FW 147.02) in 250ml water.
Thats fine.
But how you will make last 0.1M Cacl2 with 15% Glycerol for storing @ - 80oC?
Its quiety handy to make 1M cacl2 , filter it and store @ 4oC. For making 0.1 M Cacl2 just dilute it 10 times by adding to autoclaved distill water.
#5
Posted 08 October 2012 - 07:00 PM
but usually i did filter sterilization because it saves time

#6
Posted 08 October 2012 - 07:41 PM
#7
Posted 09 October 2012 - 12:18 AM
to make 50ml 0.1M Cacl2 with 15% glycerol, I would add 42.5 ml (0.1M Cacl2), 7.5ml 100% glycerol. This is OK?
Not ok.
If you add any solution to 0.1 M it will decrease its concentration. You can consider adding cacl2 to 7.5ml 100% glycerol to make it 0.1M cacl2 with 100% glycerol and add 42.5 ml (0.1M Cacl2). But filtering 100% glycerol then for sterilization will be difficult task for u.
Better make 1M cacl2. then dilute accordingly.
#8
Posted 09 October 2012 - 01:50 AM
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
#9
Posted 09 October 2012 - 02:48 AM
#10
Posted 09 October 2012 - 10:16 PM
#11
Posted 10 October 2012 - 06:00 AM
150ml waterOk,
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
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#12
Posted 10 October 2012 - 08:39 PM
#13
Posted 12 January 2015 - 07:38 AM
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