October 31st 2024
Everyone is talking about sustainability, and organizations are creating sustainability programs. But what does green chemistry really mean, and how does it apply to gas chromatography?
This review article summarizes the results obtained from the combined efforts of a joint academic and industrial initiative to solve the real-life challenge of determining low levels of peptide-related impurities in the presence of the related biologically-active peptide at a high concentration.
The LCGC Blog: Critical Evaluation of Chromatography Methods—Essential Detective Skills
October 12th 2021In this series of blog posts, I’m going to explore how the challenges of adopting methods from the literature, or from internal or external clients, can often be made easier, and more enjoyable, by taking time for some detective work prior to even entering the laboratory.
Moore’s Law in Liquid Chromatography: An Overview of 50 Years of (U)HPLC
June 1st 2020This article quantifies the progress in speed and efficiency that has been made in the area of liquid chromatography (LC) over the past 50 years. After a decade of groundbreaking advances in the 1970s, the progress in chromatographic performance over the ensuing four decades (1980–now) follows Moore’s law relatively closely. This is characteristic of technological fields that are of an evolutionary nature (that is, driven by the need for better performance).
Next Generation of Chromatographic Columns and Systems: From Theories to Possible Future Practices
May 1st 2020A series of theoretical, visualization, and simulation tools that are used to improve the structure and chemistry of the next generation of liquid chromatography (LC) columns is briefly reviewed.
Understanding How Dwell Volume Can Affect Selectivity in Reversed-Phase Gradient Chromatography
June 1st 2019The effect of dwell volume on chromatographic selectivity can be successfully modelled using retention prediction software. Hence, the robustness of reversed-phase LC gradient methodologies, with respect to dwell volume, can be conveniently assessed.
Resources for LC Practitioners in 2017: What’s on Your Bookshelf and in Your Web Browser?
December 1st 2017What are the most useful chromatography books on your bookshelf? What are the most useful web-based resources (such as websites, downloadable documents, videos) about separation science? What are the most useful tools supporting your work (such as calculators and simulators)? In this installment, Dwight Stoll compiles input from the separation science community (both individuals and vendors) to guide you to the resources that people find most useful.
The Recent Advances in Comprehensive Chromatographic Analysis of Emerging Drugs
December 1st 2017To address the challenges of analyzing new illicit drugs, emerging techniques such as UHPSFC with MS and UV detection, and GC with VUV detection, may be needed, particularly for distinguishing positional isomers and diastereomers.
(U)HPLC: The Shape of Things To Come
May 1st 2017A recent argument was raised in the scientific press that in pursuit of greater speed and separation resolution, ultrahigh performance liquid chromatography (UHPLC) is faced with practical limitations and will struggle with its own version of Moore’s law.
A Test Mixture for Performance Verification of Multi-User UHPLC–MS Instruments
March 1st 2017Chromatographic techniques with mass spectrometric detection are important enablers in modern drug discovery. With the development of robust instrumentation and implementation of user-friendly software (or software packages), non-expert users can now walk up to easily accessible advanced chromatographic systems and perform experiments at their own convenience. Although remarkable improvements in robustness and ease-of-use have happened since the introduction of the first high performance liquid chromatography–mass spectrometry (HPLC–MS) systems, the instrument performance still needs to be qualified and monitored to ensure consistent high-quality results. This article will demonstrate how a simple test mixture of carefully selected compounds can facilitate both the development of generic ultrahigh-pressure liquid chromatography–mass spectrometry (UHPLC–MS) methods and automated performance monitoring of multiple instruments located in separate laboratories and buildings.
uHPLC Teaching Assistant: A New Tool for Learning and Teaching Liquid Chromatography, Part 1
January 18th 2017The free spreadsheet-based program HPLC Teaching Assistant was developed for effective and innovative learning and teaching of liquid chromatography. This software allows teachers to illustrate the basic principles of high performance liquid chromatography (HPLC) using virtual chromatograms (simulated chromatograms) obtained under various analytical conditions. In the first instalment of this series, we demonstrate the possibilities offered by this spreadsheet to illustrate the concept of chromatographic resolution, including the impact of retention, selectivity, and efficiency; understand the plate height (van Deemter) equation and kinetic performance in HPLC; recognize the importance of analyte lipophilicity (log P) on retention and selectivity in reversed-phase HPLC mode; and manipulate or adapt reversed-phase HPLC retention, taking into account the acido-basic properties (pKa) of compounds and the mobile-phase pH.
UHPLC Instrument Variations and Approaches to Ease the Method Transfer Process
June 1st 2016UHPLC instruments from different manufacturers and instruments with different configurations can produce significant variations in chromatographic separation. The variety in instrument configuration increases the complexity of the method development process, which now requires a more thorough evaluation of the effect of instrument variations on the method. The studies presented here determined the typical inter-instrument variations in dwell volume, extra-column dispersion, and mixing efficiency as measured by mobile phase compositional accuracy. Additionally, the dwell volume and extra-column dispersion were independently and systematically varied to evaluate the resulting impact on resolution for a small molecule test mixture during gradient elution. To account for these inter-instrument variations, dwell volume and wash-out volume method translation and adjustment techniques were evaluated.
Nontargeted Metabolite Profiling in Next-Generation Plant Breeding: A Case Study in Malting Barley
December 1st 2015Non-targeted metabolite profiling by ultrahigh-performance liquid chromatography coupled with mass spectrometry (UHPLC–MS) is a powerful technique to investigate the influence of genetic and environmental influence on metabolic phenotype in plants. The approach offers an unbiased and in-depth analysis that can reveal molecular markers of desirable phenotypic traits which can be complementary to genetic markers in plant breeding efforts. Here, the power of non-targeted metabolite profiling is illustrated in a study focused on the determination of molecular markers in malting barley that are predictive of desirable malting quality for brewing applications.
Historical Developments in HPLC and UHPLC Column Technology: The Past 25 Years
November 1st 2015During the course of my scientific career beginning in the 1960s, I have grown up with the birth of modern LC column technology, the refinements of the instrumentation, and the development of widespread application of this most powerful separation and analysis technique. In this installment, I would like to share with you some of my observations and experiences with the beginning, the growth period, and the maturation of HPLC columns, where I have focused nearly 33 years of writing for this magazine. I will explore some of the early column breakthroughs beginning with the development of large superficially porous particles (SPP), the porous irregular and spherical microparticulate particles, inorganic and organic polymeric monoliths and the rebirth of the current generation of SPP. In next month’s installment I will look into my crystal ball and see what the future of HPLC and UHPLC holds.
New Chromatography Columns and Accessories for 2015
April 1st 2015Volume 33 Number 4Pages 234-247This is our annual review of new liquid chromatography (LC) columns and accessories introduced at Pittcon and throughout the previous year. This year, Michael Swartz, former author of our "Innovations in HPLC" and "Validation Viewpoint" columns, steps in as a guest columnist to write the review.
Experimental results and method validation data from two analytical case studies of complex small?molecule pharmaceuticals illustrates the utility and advantages of UHPLC in high-resolution separations.