Silica modified with polymeric amphiphilic nanoparticles as first dimension for multidimensional separation techniques.

This paper addresses the evaluation of a new amphiphilic nanoparticle supported on silica and its application as sorbent in on-line solid phase extraction. The investigated sorbent material is a copolymer composed by [2- (Acryloyloxy) ethyl] trimethylammonium chloride (block A) and butyl acrylate (block B) prepared by reversible addition-fragmentation chain transfer. After polymerization the nanoparticles were adsorbed into silica surface by electrostatic attraction providing to the sorbent both, apolar and polar characteristics. After the fundamental studies to understand the main features of the synthesized nanoparticles supported on silica, this sorbent material was packed into an extraction column. This column was connected on line with liquid chromatography-tandem mass spectrometry and utilized for automated online determination of several analytes as Ochratoxin A, azoxystrobin, cyproconazole and difenoconazole, in wine and water samples.

Evolution in miniaturized column liquid chromatography instrumentation and applications: An overview.

The purpose of this article is to underline the miniaturized LC instrumental system and describe the evolution of commercially available systems by discussing their advantages and drawbacks. Nowadays, there are already many miniaturized LC systems available with a great variety of pump design, interface and detectors as well as efficient columns technologies and reduced connections devices. The solvent delivery systems are able to drive the mobile phase without flow splitters and promote gradient elution using either dual piston reciprocating or syringe-type pumps. The mass spectrometry as detection system is the most widely used detection system; among many alternative ionization sources direct-EI LC-MS is a promising alternative to APCI. In addition, capillary columns are now available showing many possibilities of stationary phases, inner diameters and hardware materials. This review provides a discussion about miniaturized LC demonstrating fundamentals and instrumentals' aspects of the commercially available miniaturized LC instrumental system mainly nano and micro LC formats. This review also covers the recent developments and trends in instrumentation, capillary and nano columns, and several applications of this very important and promising field.