I would not take that for granted…see the comments by Tom Peat. It is easy to measure with some
coarse and the fine strips both the unbuffered cocktail and drop pH – sometimes knowing the drop pH can be relevant for the physiological state. Mixing unbuffered cocktail and stock buffer also works to give an initial idea. LGBR From: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK> On Behalf Of Jon Cooper Sent: Sunday, October 6, 2019 00:47 To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] A crystallisation screen pH query. Many thanks for the excellent replies. I am very happy with the value of 5.1 which two of you kindly sent. Best wishes Jon Cooper On 5 Oct 2019 22:51, Bob Cudney <b...@hrmail.com <mailto:b...@hrmail.com> > wrote: Hello Jon, That JCSG+ reagent is a copy of Hampton Research PEG/Ion reagent 48. While there is no pH adjustment made during the formulation of this reagent, the 20% w/v PEG 3350, 0.2 M Ammonium citrate dibasic in deionized water results in a measured pH at 25 degrees Celsius of 5.1. The formulation as well as measured pH, refractive index, conductivity and other details can be found here https://hamptonresearch.com/product-PEG-Ion-PEG-Ion-2-PEG-Ion-HT-11.html under the Support Material(s). Hope this helps. Kind Regards, Bob Cudney From: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK <mailto:CCP4BB@JISCMAIL.AC.UK> > On Behalf Of Jon Cooper Sent: Saturday, October 5, 2019 2:10 PM To: CCP4BB@JISCMAIL.AC.UK <mailto:CCP4BB@JISCMAIL.AC.UK> Subject: [ccp4bb] A crystallisation screen pH query. Does anyone know the pH of JCSG+ condition A3 which is stated as 0.2 M ammonium citrate dibasic, 20% (v/v) PEG3350. I can't really measure it myself, so any help much appreciated! _____ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB <https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1> &A=1 _____ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB <https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1> &A=1 ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
