Preparation of open‐tubular CEC column bonded with 6‐O‐monotosyl‐deoxy‐β‐cyclodextrin and its application in the enantioseparation of several related benzimidazoles

Preparation of β-cyclodextrin covalent organic framework-immobilized poly(glycidyl methacrylate) nanoparticle-coated open tubular capillary electrochromatography column for chiral separation

A new enantioselective open-tubular capillary electrochromatography was developed employing poly(glycidyl methacrylate) nanoparticles/β-cyclodextrin covalent organic frameworks chemically immobilized on the inner wall of the capillary as a stationary phase. A pretreated silica-fused capillary reacted with 3-aminopropyl-trimethoxysilane followed by poly(glycidyl methacrylate) nanoparticles and β-cyclodextrin covalent organic frameworks through a ring-opening reaction. The resulting coating layer on the capillary was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The electroosmotic flow was studied to evaluate the variation of the immobilized columns. The chiral separation performance of the fabricated capillary columns was validated by the analysis of the four racemic proton pump inhibitors including lansoprazole, pantoprazole, tenatoprazole, and omeprazole. The influences of bonding concentration, bonding time, bonding temperature, buffer type and concentration, buffer pH, and applied voltage on the enantioseparation of four proton pump inhibitors were investigated. Good enantioseparation efficiencies were achieved for all enantiomers. In the optimum conditions, the enantiomers of four proton pump inhibitors were fully resolved within 10 min with high resolutions of 9.5-13.9. The column-to-column and inter- to intra-day repeatability of the fabricated capillary columns through relative standard deviation were found better than 9.54%, exhibiting satisfactory stability and repeatability of the fabricated capillary columns.

Progress of Pretreatment and Analytical Methods of Proton Pump Inhibitors: An Update since 2010

Proton pump inhibitors (PPIs) are the most commonly used medication for stomach secretion disorders. However, when it comes to safe, discreet pharmaceutical practice, widely recognized preparational and analytical method(s) for PPIs with sensitivity, selectivity, speed and high accuracy still remains underdeveloped. For this reason, this paper sets out to make a comprehensive review of the preparation and determination methods for PPIs based on multiple matrices since 2010. We have integrated newly-developed techniques (such as solid phase extraction, liquid phase micro-extraction, and solid phase micro-extraction) into conventional sample preparational methods. On the other hand, our analytical techniques include liquid chromatography, supercritical fluid chromatography, capillary electrophoresis, and employment of sensors. In addition, we have identified the pros and cons of each technique and have forecast their future developmental trends.

β-Cyclodextrin covalent organic framework supported by polydopamine as stationary phases for electrochromatographic enantioseparation

In this work, a new open-tubular capillary electrochromatography (OT-CEC) column was prepared using β-cyclodextrin covalent organic framework (β-CD COF) as a stationary phase. Polydopamine was used to assist fabrication of β-CD COF on an inner wall of a fused-silica capillary. The coating layer on the capillary was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Electroosmotic flow (EOF) was also studied to evaluate the variation of the inner wall of immobilized columns. Furthermore, the chiral separation effectiveness of the fabricated capillary column was evaluated by CEC using enantiomers of several related proton pump inhibitors as model analytes, including omeprazole, lansoprazole, pantoprazole and tenatoprazole. The effects of bonding time and concentration of β-CD COF, the type, concentration and pH of buffer, applied voltage were investigated to obtain satisfactory enantioselectivity. In the optimum conditions, the enantiomers of four analytes were resolved within 15 min with resolutions of 1.63-2.62. The relative standard deviation values for migration times and resolutions of the analytes representing intraday and interday were less than 6.75% and 4.24%, respectively. The results reveal that β-CD COF has great potential as chiral-stationary phases for enantioseparation in CEC.

Preparation of a polydopamine/β-cyclodextrin coated open tubular capillary electrochromatography column and application for enantioseparation of five proton pump inhibitors

An open tubular capillary electrochromatography column was prepared by immobilizing β-cyclodextrin on the inner wall of pretreated capillary via noncovalent adsorption of polydopamine. The resulting coating layer on the capillary was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. Electroosmotic flow was studied to evaluate the variation of the immobilized columns. The prepared columns showed good chiral separation performance toward five proton pump inhibitors including lansoprazole, pantoprazole, tenatoprazole, rabeprazole, and omeprazole. The influences of β-cyclodextrin concentration, coating time, buffer pH, buffer concentration, and applied voltage on separation were investigated. In the optimum conditions, the enantiomers of five analytes were fully resolved within 15 min with high resolutions of 4.57 to 8.13. The method was extensively validated in terms of accuracy, precision, and linearity and proved to be robust. The relative standard deviation values for migration times and peak areas of the analytes representing intraday and interday were less than 1.9 and 3.6%, respectively. Further, the polydopamine/β-cyclodextrin coated capillary column could be successively used over 100 runs without showing significant decrease in the separation efficiency.