最好是磷酸盐缓冲液

磷酸盐缓冲溶液不适用此pH，可以使用以下缓冲溶液：

Neutralized Phthalate Buffer, pH 4.4
Place 50 mL of the potassium biphthalate solution in a 200-mL volumetric flask, add the specified volume of the sodium hydroxide solution, then add water to volume.
0.2 M NaOH, 6.6mL
Potassium Biphthalate, 0.2 M: 40.85 g/L of potassium biphthalate in water.

Citrate Buffer, pH4.4
Mix 0.1 M Citric Acid with 0.1 M Sodium Citrate in the proportions given below.
0.1 M Citric Acid, 49.5mL + 0.1 M Sodium Citrate, 50.5mL

Acetate Buffer, pH 4.3
Place the specified amount of sodium acetate NaC2H3O2·3H2O in a 1000-mL volumetric flask, add the specified volume of the acetic acid solution, then add water to volume, and mix.
NaC2H3O2 · 3H2O, 1.99g + 2 N CH3COOH, 17.7mL

Acetate Buffer, pH 4.5
Place the specified amount of sodium acetate NaC2H3O2·3H2O in a 1000-mL volumetric flask, add the specified volume of the acetic acid solution, then add water to volume, and mix.
NaC2H3O2 · 3H2O, 2.99g + 2 N CH3COOH, 14.0mL，

自己算呀