All News
Analysis of Residual Antimicrobials in Meat Using HPLC
June 6th 2017Analysis of residual antimicrobials in animal products is crucially important to ensure food safety. This article presents a simple, fast, and highly sensitive high performance liquid chromatography (HPLC) assay of regulated antimicrobials, as well as sample preparation and purification methods. Twenty-four different analytes of interest were investigated in beef, pork, and chicken meat samples.
Enantiomeric Separation of Privileged Scaffold Derivatives in Early Drug Discovery Using Chiral SFC
June 6th 2017Successful therapeutic intervention often requires chiral medicines because of the intrinsic chirality of protein drug targets, which consist of L-amino acids. Potency, efficacy, and safety can be highly dependent on the precise stereochemical geometry of the molecules. Determining the biological profile of individual enantiomers in the early stages of drug discovery is important for successful optimization towards clinical candidates. Here we demonstrate the benefits of supercritical fluid chromatography (SFC) with three chiral stationary phases exemplified by high frequency resolution of 41 out of 50 chiral derivatives of eight commonly used drug discovery scaffolds including 1,3-thiazoles, 1,3-benzothiazoles, pyranoquinolones, indoles, and leucolines.
The LCGC Blog: Getting the Best Repeatability from Your Quantitative Gas Chromatography
June 2nd 2017I’m often asked “what reproducibility should I expect to get from my [insert instrument manufacturer and model]?” So, most folks are referring to the repeatability aspects of precision, as in: “what relative standard deviation (usually expressed at %RSD) for peak area or quantitative result should I be able to achieve from repeat injections from a single vial of sample?”
Evaluation of Retention and Selectivity Using Biphenyl Stationary Phases
June 1st 2017In reversed-phase liquid chromatography (LC), C18 alkyl-based stationary phases have been the favourite of method developers. Phenyl stationary phases are an alternative that are thought to benefit from additional π-π mechanisms. Recently, there has been a growing interest in the use of phases based on the biphenyl moiety. This instalment of “Column Watch” looks at the retention mechanisms of biphenyl phases and contrasts them with those of more-common alkyl phases.
In the 21st century, numerous advances have been made in liquid chromatography (LC) column technology. The best known are columns packed with sub-2-µm porous particles or sub-3-µm superficially particles, and monolithic columns. Another very novel and original development is micro-pillar array columns (µPAC). µPACs are produced by a lithographic etching process to create a perfectly ordered separation bed on a silicon chip. Although the performance in terms of efficiency has been illustrated, the applicability for analysis of real complex samples has yet to be fully demonstrated. This article illustrates that state‑of‑the‑art µPAC columns coated with octadecyl are applicable for a challenging application such as lipidomics. The performance is illustrated with the analysis of human blood plasma lipids.
Mixed-Mode Chromatography—A Review
June 1st 2017Mixed-mode high performance liquid chromatography (MM-HPLC) involves the combined use of two (or more) retention mechanisms in a single chromatographic system. Many original stationary phases have been proposed in recent years with promising possibilities, while applications have only started to appear in the literature. In this review, the authors discuss mixed-mode chromatography stationary phases. An overview of applications using mixed-mode chromatography is described, as well as the increased interest in mixed-mode systems for two-dimensional chromatography.
Trends in Enantioselective High Performance Liquid Chromatography
June 1st 2017Enantioselective high performance liquid chromatography (HPLC) is slowly adopting the modern particle technologies (sub-2-µm fully porous particles [FPPs] and sub-3-µm superficially porous silica particles [SPPs]) that have been well known in reversed-phase LC for the past decade. The most significant benefit is that enantiomer separations can be performed much faster, which is of interest in high-throughput screening applications and multidimensional enantioselective HPLC analysis. The state of the art is briefly discussed with some examples documenting the potential of core–shell particle technology and comprehensive multidimensional separations.
Computer-Assisted Method Development for Small and Large Molecules
June 1st 2017The aim of this article is to illustrate the current status of computer-assisted method development and retention modelling. This study focuses on the successful method development of typical small pharmaceutical compounds (impurity profiling) and large therapeutic proteins. By choosing appropriate initial conditions, the method development can be performed in less than one day. However, for small molecules possessing different physicochemical properties, the conditions can be multifarious, while for biopharmaceuticals (for example, monoclonal antibodies [mAbs], antibody–drug conjugates [ADCs]), a generic method can easily be developed. In addition to retention modelling and optimization, the potential of simulated robustness testing is also demonstrated. Depending on the applied retention model, the impact of any change among six experimental parameters (tG, T, pH, ternary composition, flow rate, and initial- and final mobile phase compositions) on the separation can be assessed using a 26 or 36 type virtual
