bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Frank von
Delft
Sent: 24 August 2011 22:21
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Aging PEGs
And now, does anybody know of systematic data indicating how consistently
all this matters?
phx
On 24/08/2011 21:45, Prince, D
] On Behalf Of
Jacob Keller
Sent: Wednesday, August 24, 2011 3:18 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] Aging PEGs
A while ago I measured the pH's of old and new PEGs and found them
very different, and internally attributed all old vs new PEG issues
to pH. Upon reflection, this seems too
board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Jacob
Keller
Sent: Wednesday, August 24, 2011 2:18 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] Aging PEGs
A while ago I measured the pH's of old and new PEGs and found them very
different, and internally attributed all old vs new PEG issues
to pH
Commercial polyethylene glycol is contaminated with polymers that have aldehyde
groups at the ends. Other impurities include some amount of internal epoxide
linkages. The aldehyde groups can be additionally oxidized to carboxylic
acids. I would assume that oxidation to terminal carboxylic
: [ccp4bb] Aging PEGs
A while ago I measured the pH's of old and new PEGs and found them
very different, and internally attributed all old vs new PEG issues
to pH. Upon reflection, this seems too simplistic. Are there other
known mechanisms of crystallization capacities of PEGs of various
ages?
Jacob
] On Behalf Of
Jacob Keller
Sent: Wednesday, August 24, 2011 3:18 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] Aging PEGs
A while ago I measured the pH's of old and new PEGs and found them
very different, and internally attributed all old vs new PEG issues
to pH. Upon reflection, this seems too
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-Original Message-
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of
Jacob Keller
Sent: Wednesday, August 24, 2011 3:18 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] Aging PEGs
A while ago I measured
: [ccp4bb] Aging PEGs
And now, does anybody know of systematic data indicating how consistently
all this matters?
phx
On 24/08/2011 21:45, Prince, D Bryan wrote:
For those of us truly controlling types :), I used to make the PEG
solutions and filter them over a Bio-Rad resin that filtered
