Importance of Particle Pore Size in Determining Retention and Selectivity in Reversed Phase Liquid Chromatography.

Column selection often centers on the identification of a stationary phase that increases resolution for a certain class of compounds. While gains in resolution are most affected by selectivity of the stationary phase or modifications of the mobile phase, enhancements can still be made with an intentional selection of the packing material's microstructure. Unrestricted mass transfer into the particle's porous structure minimizes band broadening associated with hindered access to stationary phase. Increased efficiency, especially when operating above the optimal flow rates, can be gained if the pore size is significantly larger than the solvated analyte. Less studied are the effects of reduced access to pores due to physical hindrance and its impact on retention. This article explores the relationship between pore size and reversed phase retention, and specifically looks at a series of particle architectures with reversed phase and size exclusion modes to study retention associated with access to stationary phase surface area.

A low-cost, open-source digital stripchart recorder for chromatographic detectors using a Raspberry Pi.

One of the most critical aspects of chromatographic analysis is effective data acquisition and processing. Typical approaches include software platforms designed for specific instruments or commercial data acquisition hardware boards, both of which require expensive licenses to use and operate. To increase the access and affordability of chromatographic data acquisition, especially for systems in which software control has become obsolete or must be written in-house, an open-source digital stripchart recorder has been developed. This system is built upon a Raspberry Pi single-board computer and a plug-in printed circuit board with the necessary integrated circuits for data acquisition. Using an open-source software called Processing, a complete user interface to control the system was developed that enables the acquisition, filtering, and processing of chromatographic data. The system performs comparably to more expensive platforms, with calculated values for peak area, retention time, and plate count all within 3% of the values calculated by a widely used commercial chromatography data software package.