A new approach for the determination of the iso-electric point of nanoparticles

作者：Pan, Rongjun^*; Liew, Kongyong; Xu, Liusu; Gao, Yuran; Zhou, Juying; Zhou, Hongwei

来源：Colloids and Surfaces A: Physicochemical and Engineering Aspects , 2007, 305(1-3): 17-21.

DOI：10.1016/j.colsurfa.2007.04.035

• iso-electric point
• UV-vis absorption spectroscopy
• nanoparticles
• ultrasonication

A new and simple experimental approach is proposed for the determination of iso-electric point (IEP) of nanoparticles suspension using ultraviolet-visible absorption spectroscopy. The suspension was first ultrasonicated to obtain appropriate particle dispersion and the optimal ultrasonication time was investigated by measuring the UV-vis spectra. The absorbance of the suspensions was then determined as a function of pH values. The absorbance at lambda = 245 run changed from positive to negative after the weakest absorbance was reached. The point of intersection of y = 0 and the curve indicates the IEP of the nanoparticle dispersion. The value so obtained was close to those determined by the conventional electrokinetic method and from prediction.

• 出版日期2007-9-15
• 单位广西科技大学; 中南民族大学