Continuous full filling capillary electrochromatography: Nanoparticle synthesis and evaluation

Reversed phase continuous full filling capillary electrochromatography with electrospray ionisation mass spectrometric detection was performed with highly sulphated poly [styrene-co-(lauryl methacrylate)-co-(divinylbenzene)] nanoparticles. The nanoparticles that contained a hydrophobic core and a hydrophilic surface were prepared in a one step synthesis using soap free emulsion polymerisation. By changing the concentration of monomers, the polymerisation temperature, and the polarity of the dispersive phase, the size of the nanoparticles could be controlled. With the optimised conditions, nanoparticles with an average size of 157 nm were obtained. These nanoparticles were dispersed in the background electrolyte and used for reversed phase continuous full filling. An orthogonal electrospray ionisation interface was used to separate the eluting nanoparticles from the eluting analytes prior to mass spectrometry detection. Compared to previous studies on reversed phase continuous full filling, the retention, the separation efficiency, and the resolution of a homologous series of dialkyl phthalates were greatly improved.