Knowledge Base

In porous chromatographic packing materials, more than 95% of interactions between the stationary phase and target analytes occur within the pores, which makes pore size one of the most important parameters of a packing material. In this article, we discuss the relationship between column pore size and target molecular weight, and share a real-world application case where a 300Å column outperform a 120Å column in the analysis of a large molecular weight analyte.

The 2026 Welch Materials Cup Chromatography Competition, held in China from July to August 2026, featured a number of questions designed to assess more than simple knowledge recall. Many of the questions focused on the ability to connect chromatographic theory with practical applications and to apply fundamental principles when faced with complex analytical conditions. In this article, we have selected 11 representative questions that showed the highest error rates and translated both the questions and their detailed analyses into English.

In analytical chemistry, spiked recovery rate is a fundamental parameter used to evaluate the accuracy of an analytical method. In this article, we explore the three categories of spiked recovery experiments, the calculation of spiked recovery rate and required spiking amount, and the practical experimental guidelines for a valid experiment.

In introductory liquid chromatography training, almost every beginner has heard the following statement: “In reversed-phase chromatography, more polar compounds elute first, while less polar compounds elute later.” But chromatography is not that simple. In this article, we discuss factors beyond polarity that determines elution order.

In modern analytical chemistry, UHPLC offers significant benefits, including increased throughput, superior resolution, and reduced solvent consumption. However, transferring methods from HPLC to UHPLC is more than simply swapping columns. In this article, we explore the essentials in transferring a method, from mathematical calculation to method validation.

HPLC has been one of the most widely used analytical chromatographic techniques, yet it is not fast enough to meet every laboratory analysis. In this article, we explore UHPLC, the faster version of liquid chromatography, compare the differences between UHPLC and HPLC, and discuss the limitations and application fields of UHPLC.

The existence of hydrogen bonding in acetonitrile-water solutions is a fundamental question. In this article, we will discuss the question in details, including the physicochemical properties of acetonitrile and water, the interaction that takes place when acetonitrile is dissolved in water, and the abnormalities that may occur when using acetonitrile-water solutions as mobile phase or for sample extraction.

Poor resolution is challenging, but elution order reversal is even perplexing. In this article, the author discusses three primary factors that cause peaks to elute inversed when mobile phase changes: pH, organic modifier, and buffer salt.

Reproducibility issues are an unavoidable topic in HPLC. In this article, we break down easily overlooked, application-level factors that cause reproducibility failures into four aspects: reagents, samples, instruments, and columns, and provide a practical troubleshooting framework to help chromatographers isolate issues and achieve robust, consistent separation results in daily laboratory practice.

Unexplained peak fronting and split peaks often compromise HPLC data quality. Among all possible culprits, solvent effect is the one often overlooked. This article explores the mechanisms of this hidden killer and provides actionable strategies to restore peak symmetry.

In this article, we discuss the catastrophic results one would get if they replace formic acid in the mobile phase by acetic acid in an HPLC experiment.

In this article, we explore a novel analytical approach utilizing the ionic liquid [EimHSO4] for copper ion extraction. By examining its unique phase separation and coordination mechanisms, it highlights how this innovative methodology could pave the way for future LC-MS sample preparation and quantification.