PMSF precipitate? - (Nov/30/2008 )
I am using the protease inhibitor PMSF during the ChIP sonication step. I did not prepare the 0.1M solution and had a question about it.
It is not frozen at -20 degrees so I assume it was prepared in isopropanol (that is the correct solvent?) but there is a precipitate in the solution, is this normal? It is difficult to pipette into a 1000ml tip and am wondering if I need to allow it to come to room temperature before attempting to use it (like my SDS solution).
Appreciate your time,
Stephen
It is not frozen at -20 degrees so I assume it was prepared in isopropanol (that is the correct solvent?) but there is a precipitate in the solution, is this normal? It is difficult to pipette into a 1000ml tip and am wondering if I need to allow it to come to room temperature before attempting to use it (like my SDS solution).
Appreciate your time,
Stephen
If the PMSF was properly dissolved in the first place, then I don't believe that there should be any precipitate in it - I've never noticed any. Perhaps they used a different solvent (not isopropanol). You might be better off to start fresh and make your own stock vial.
Plus PMSF in isoprop is prompt to precipitate. Keep your solution in a warm (RT should do it!) place, protected from light.
dissolve PMSF powder in isopropanol. keep in -20c. shake before use. it always forms cystal. it's normal.
It is not frozen at -20 degrees so I assume it was prepared in isopropanol (that is the correct solvent?) but there is a precipitate in the solution, is this normal? It is difficult to pipette into a 1000ml tip and am wondering if I need to allow it to come to room temperature before attempting to use it (like my SDS solution).
Appreciate your time,
Stephen
If the PMSF was properly dissolved in the first place, then I don't believe that there should be any precipitate in it - I've never noticed any. Perhaps they used a different solvent (not isopropanol). You might be better off to start fresh and make your own stock vial.
guess I've never kept it frozen - good to know!
Appreciate all the help! Apparently it was dissolved in ethanol, but after letting it come to RT the crystals went away, need more patience in life.
Thanks