On Thursday, June 19, 2014 11:28:59 PM UTC+8, [email protected] wrote: > 在 1994年2月11日星期五UTC-6下午2时07分56秒，Ross Whetten写道： > > > The CRC Handbook of Biochemistry gives the composition of McIlvaine buffer > > > as a mixture of 0.1 molar citric acid and 0.2 molar disodium phosphate. > > > Depending on the pH you want, you mix varying amounts of the two components > > > together. For example, 98 ml of citric acid + 2 ml of Na2HPO4 gives pH 2.2, > > > 42 ml of citric acid + 58 ml Na2HPO4 gives pH 5.6, and 2.75 ml citric acid > > > and 97.25 ml Na2HPO4 gives pH 8.0 (all pH determinations given at 21 C). > > > > > > > > > > > > Ross Whetten > > > Research Assistant Professor > > > Forest Biotechnology Group > > > North Carolina State University > > > Raleigh, North Carolina 27695-8008 USA > > > telephone or fax (919)515-7801 > > > e-mail [snip]@unity.ncsu.edu > > > -- > > > > > > > > > Ross Whetten > > > Research Assistant Professor > > > > > > I am wondering what is the salt concentration of this buffer? > > If we perpare some standard buffer like 1 M phosphate buffer, we always > adjust pH by mixing 1M acid (monobasic) with the same concentraiton of base > (dibasic). > > > > Chao
In the protocol, the components are 0.1M and 0.2M. As an approximation, the ratio of the compounds determines pH. The concentration determines the buffering capacity. HTH Wo _______________________________________________ Methods mailing list [email protected] http://www.bio.net/biomail/listinfo/methods
