Polar-embedded and polar-endcapped phases have become widespread over the past decade. When compared to classical alkylsilicas, they offer an alternative selectivity profile, increased stability in highly aqueous mobile phases, and improved peak shape for basic analytes. This mini-review summarizes current knowledge and applications of these phases, including the recent development of a series of N-methylamide embedded phases, prepared using supercritical carbon dioxide.

The application of chemical-modified gold nanoparticles (GNPs) as chiral selector for the enantioseparation based on pseudostationary phase-CEC (PSP-CEC) is presented. GNPs modified by thiolated beta-CD were characterized by NMR and FT-IR. The nanoparticle size was determined to be of 9.5 nm (+2.5 nm) by Transmission Electron Microscopy (TEM) and UV spectra. Four pairs of dinitrophenyl-labeled amino acid enantiomers (DL-Val, Leu, Glu and Asp) and three pairs of drug enantiomers (RS-chlorpheniramine, zopiclone and carvedilol) were analyzed by using modified GNPs as the chiral selector in PSP-CEC. Good theoretical plate number (up to 2.4x10(5) per meter) and separation resolution (up to 4.7) were obtained even with low concentration of modified GNPs (0.8-1.4 mg/mL). The corresponding concentration of beta-CD in the buffer was only 0.30-0.53 mM, which was much lower than the optimum concentration of 15 mM if pure beta-CD was used as chiral selector. Our results showed that thiolated beta-CD modified GNPs have more sufficient interaction with the analytes, resulting in significant enhancement of enantioseparation. The study shed light on potential usage of chemical modified GNPs as chiral selector for enantioseparation based on PSP-CEC.

This study revealed that a Pseudomonas aeruginosa tonB1 mutant was unable to produce a mature biofilm and showed reduced swarming and twitching motilities compared with the parent strain. The tonB1 mutant was also found to produce significantly lower cell-free and cell-associated levels of the quorum sensing (QS) signal molecule 3-oxo-C12-AHL. Altered biofilm and motility phenotypes were restored to wildtype with the addition of exogenous N-acylhomoserine lactones. These functions were independent of the role of TonB1 in iron uptake. This is the first time that a link has been established between TonB1 activity and QS.

A mechanistic approach was undertaken to understand the oxygen sensitivity of a Pd-catalyzed amination reaction used in the synthesis of an active pharmaceutical ingredient. FlowNMR and dissolved oxygen probes were used as process analytical technology alongside kinetic and unit operation models to better characterize the oxidative deactivation pathways of the catalyst. Interplay between ligand excess, oxygen inertion, and additional degassing due to reflux were all found to contribute to reaction rate variability. This mechanistic approach allowed for appreciation and clear communication of the risks, development of protocols to mitigate those risks, and successful scale-up under rapid development timelines.

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In this work, a capillary electrophoretic method for the rapid quantitation of atorvastatin (AT) in a lipitor tablet was investigated and developed. Method development included studies of the effect of applied potential, buffer concentration, buffer pH, and hydrodynamic injection time on the electrophoretic separation. The method was validated with regard to linearity, precision, specificity, LOD, and LOQ. The optimum electrophoretic separation conditions were 25 mM sodium acetate buffer at pH 6, with a separation voltage of 25 kV using a 50 microm capillary of 33 cm total length. Sodium diclofenac was used as an internal standard. Analysis of AT in a commercial lipitor tablet by electrophoresis gave quite high efficiency, coupled with an analysis time of less than 1.2 min in comparison to LC. Once the separation was optimized on capillary, it was further miniaturized to a microchip platform, with linear imaging UV detection using microchip electrophoresis (MCE). Linear imaging UV detection allowed for real-time monitoring of the analyte movement on chip, so that the optimum separation time could be easily determined. This microchip electrophoretic method was compared to the CE method with regard to speed, efficiency, precision, and LOD. This work represents the most rapid and first reported analysis of AT using MCE.

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