The Column
The design of strategies to reduce the activity of residual silanols in conventional alkyl-bonded columns is still one of the main challenges in the current separation of basic compounds by reversed-phase liquid chromatography.
The design of strategies to reduce the activity of residual silanols in conventional alkyl-bonded columns is still one of the main challenges in the current separation of basic compounds by reversed-phase liquid chromatography. The addition of reagents, such as amines, surfactants and ionic liquids to the hydro-organic mobile phases is a useful option that provides enhanced results. The effectiveness of an additive to suppress the silanol activity can be measured based on the changes produced in retention or peak shape. The former option cannot be applied when the anion in the additive is adsorbed on the stationary phase, at least partially. Based on the fact that the main interest in blocking the residual silanols is the enhancement in peak shape, a simple, reliable, practical and illustrative way of characterizing the peak performance using the information provided by the plots of the left and right peak half-widths versus the retention time was developed. This approach is applied here to a variety of C18 columns and additives.
USP CEO Discusses Quality and Partnership in Pharma
December 11th 2024Ronald Piervincenzi, chief executive officer of the United States Pharmacoepia, focused on how collaboration and component quality can improve worldwide pharmaceutical production standards during a lecture at the Eastern Analytical Symposium (EAS) last month.
Overcoming Common Challenges to Determine Residual Impurities Using IC in APIs with Limited Water
December 10th 2024Organic solvents are generally not compatible with ion chromatography (IC) systems. The approach presented here assists the use of organic solvents for sample preparation and provides a mechanism for the removal of the organic solvents from the chromatographic flow path.
The Benefits of DBS-GC–MS/MS in Barbiturate Detection
December 5th 2024Three analytical and two pre-treatment methods—gas chromatography–mass spectrometry (GC–MS), gas chromatography–tandem mass spectrometry (GC–MS/MS), and liquid chromatography–tandem mass spectrometry (LC–MS/MS) plus liquid-liquid extraction (LLE) and dried blood spot (DBS) —were compared for the quantitation and characterization of barbiturates.
Pharmaceutical excipients, such as polyethylene glycol-based polymers, must be tested for the presence of ethylene oxide (EtO) and 1,4-dioxane as part of a safety assessment, according to USP Chapter <228>.