Standard buffer recipes

TABLE 8 Standard Buffer Recipes for Initial Experiments... 

For example, to prepare a pH = 9 buffer solution, one would prepare a solution of ammonium chloride (refer to Table 5.1), and then add a solution of sodium hydroxide while stirring and monitoring the pH with a pH meter. The preparation is complete when the pH reaches 9. The required conjugate acid-base pair would be NH3 - NHj. Recipes for standard buffer solutions can be useful. Table 5.2 gives specific directions for preparing some popular buffer solutions. 

Two basic gel running buffer recipes are standard, Tris-acetate (TAE) and Tris-borate (TBE) we use the latter, and this is included in the recipes given below. 

The standard buffer solutions have been developed in a way so that each of them should have (1) inexpensive chemicals, (2) simple recipe, and (3) reproducibility and stability in time. 

Hold buffer at 30°C and aerate with a stream of bubbles via a fine capi llary tube. An aquarium aerator is a convenient way to achieve this. Select the buffer and pH to suit the enzyme being investigated. Citrate/phosphate (Mcllvaine s) buffer (appendix 2A)in the pH range of 4.0 to 6.5 is usually satisfactory for the assay of most DPOs. Recipes for a wide range of buffer solutions may be found in appendix 2a or in any standard textbook of practical biochemistry (for example, Dawson et al 1986). 

Procedures. A standard recipe for the latex preparation is shown below (St + M2) 20 g, (water + buffer) 160 g, and initiator 5 mmole/1. The weight fraction of M2 in monomer charge (f) was varied from 0.01 to 0.50. Polymerizations were carried out at 55°C or 70°C and pH 2.5 or 9.0 under nitrogen. Samples were withdrawn from the reaction mixture at various time intervals and the polymer was precipitated in an excess of acetone. The conversion and polymer composition were determined by gravimetric means and by elemental analysis, respectively. The M2 fraction in instantaneously-formed copolymer ( Fi ) was calculated from eq. 1 ... 

Washing solution 20 x SSC buffer standard sodium citrate solution for a 20x SSC solution dissolve 701.28 g NaCl and 352.92 g NaCitrate in a recipe to make 4 1 (check to have pH to 7.0) and bring final volume to 4 1, then Autoclave the solution in order to be RNAse free). 

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