When screening the pH for crystallization conditions, it is desirable to avoid extra variables that result from the various buffers typically used for adjusting various pH. Therefore we offer the JBScreen pH-2D that consists of broad-range buffers covering the whole range from pH 4 to 10 . They allow broad pH screening but keep the chemical nature of the solution thus, avoiding overlaying effects that would inevitable result from use of conventional buffers.
JBScreen pH-2D contains six extended range buffer systems; each composed of a mixture of three individual buffers with a distinct chemical nature and well separated pKa values. Each buffer system is composed of a low-pH and a high-pH stock solution, supplied in 10 ml volumes. The low-pH stock solution is preset at pH 4.0 and the high-pH solution at either pH 9.0 or 10.0 (see download). Thus, mixtures of the low-pH and high-pH stock solutions in different proportions allow to cover the entire pH range from 4.0 – 9.0 or 4.0 – 10.0, respectively. The composition of the buffer systems assures a virtually linear distribution of the resulting pH vs the percentage of high pH / low pH stock.
Larger volumes are available upon request.
 Newman (2004) Novel buffer systems for macromolecular crystallization. Acta Cryst. D 60:610.
Individual Conditions of all screens are available in 10 ml as well as 100 ml volumes.