Passive adsorption is said non pH dependent. This is particularly true for polyclonal antibodies.

However, numerous results indicate that pH should be considered during passive adsorption.

For example, it has been shown that passive adsorption can be affected by a variation of pH. The maximum of adsorbed IgG onto poly(vinyltoluene) particles is 2.6 mg/m² at pH = 4 and pH = 10, whereas it is 7.5 mg/m² at pH = 7.8.

When changing the pH from 7.8 to 4 (or 7.8 to 10), a partial desorption of IgG was observed (values changed from 7.5 to 3.2 mg/m²).

Literature

Bagghi P. and al. J.Colloid Interface Sci. 1981, 83 : 460-478.