The isoelectric point (IEP) is the pH value where the zeta potential is zero.can be determined by the Nicomp 380 ZLS by titrating the sample and recording zeta potential as a function of pH. 
等电点可以通过滴定样品PH值，再用Nicomp 380 ZLS 记录Zeta电位，Zeta电位为0时的PH值就是等电点。