Simultaneous detection of a wide range of synthetic and natural dyes in artworks using UHPLC-PDA-HRMS.

This paper presents a validated method using ultra-high pressure liquid chromatography with photodiode array detection coupled to high-resolution mass spectrometry (UHPLC-PDA-HRMS) for the simultaneous analysis of a wide range of natural and synthetic organic colourants, including neutral, acidic and basic dyes. In total, 30 natural and 62 synthetic organic dye reference samples (which contain 118 compounds because some of the dyes are composed of mixtures) were analysed. The method demonstrated good linearity for the 12 dyes selected for method validation achieving correlation coefficients (R) exceeding 0.

Incorporating a liquid-core-waveguide cell in recycling liquid chromatography for detailed studies of photodegradation reactions.

In this work, a microfluidic photoreactor was embedded in a recycling liquid-chromatography system. Mixtures were separated on an analytical column and compounds of interest were subsequently introduced into the light-reactor cell. After degradation, the content of the light-reactor cell was reinjected onto the same column to separate the parent compound from its degradation products.

Assessing the feasibility of stationary-phase-assisted modulation for two-dimensional liquid-chromatography separations.

Two-dimensional liquid chromatography (2DLC) offers great separation power for complex mixtures. The frequently encountered incompatibility of two orthogonal separation systems, however, makes its application complicated. Active-modulation strategies can reduce such incompatibility issues considerably.

Combining Photodegradation in a Liquid-Core-Waveguide Cell with Multiple-Heart-Cut Two-Dimensional Liquid Chromatography.

Photodegradation greatly affects everyday life. It poses challenges when food deteriorates or when objects of cultural heritage fade, but it can also create opportunities applied in advanced oxidation processes in water purification. Studying photodegradation, however, can be difficult because of the time needed for degradation, the inaccessibility of pure compounds, and the need to handle samples manually.

Liquid Core Waveguide Cell with In Situ Absorbance Spectroscopy and Coupled to Liquid Chromatography for Studying Light-Induced Degradation.

In many areas, studying photostability or the mechanism of photodegradation is of high importance. Conventional methods to do so can be rather time-consuming, laborious, and prone to experimental errors. In this paper we evaluate an integrated and fully automated system for the study of light-induced degradation, comprising a liquid handler, an irradiation source and exposure cell with dedicated optics and spectrograph, and a liquid chromatography (LC) system.

Characterization of a liquid-core waveguide cell for studying the chemistry of light-induced degradation.

Many organic compounds undergo changes under the influence of light. This might be beneficial in, for example, water purification, but undesirable when cultural-heritage objects fade or when food ingredients (e.g.

Measuring and using scanning-gradient data for use in method optimization for liquid chromatography.

The use of scanning gradients can significantly reduce method-development time in reversed-phase liquid chromatography. However, there is no consensus on how they can best be used. In the present work we set out to systematically investigate various factors and to formulate guidelines.

Recent applications of retention modelling in liquid chromatography.

Recent applications of retention modelling in liquid chromatography (2015-2020) are comprehensively reviewed. The fundamentals of the field, which date back much longer, are summarized. Retention modeling is used in retention-mechanism studies, for determining physical parameters, such as lipophilicity, and for various more-practical purposes, including method development and optimization, method transfer, and stationary-phase characterization and comparison.

Development and validation of an analytical protocol for the sampling and quantitative analysis of ions on the surface of unstable historic glass in museum collections using ion-exchange chromatography.

The early identification of unstable glass objects in museum collections is essential for their conservation, but as yet cannot be accomplished straightforwardly. Accordingly, this paper describes the development and validation of a simple protocol for quantitative determination of ions characteristic of the chemical decay of historic glass, using surface swabbing combined with ion-exchange chromatography. The establishment of a robust protocol is an important step in the development of an early warning system for the chemical deterioration of unstable glass.

Characterization of Dye Extracts from Historical Cultural-Heritage Objects Using State-of-the-Art Comprehensive Two-Dimensional Liquid Chromatography and Mass Spectrometry with Active Modulation and Optimized Shifting Gradients.

Unbiased characterization of dyes and their degradation products in cultural-heritage objects requires an analytical method which provides universal separation power regardless of dye classes. Dyes are small molecules that vary widely in chemical structure and properties, which renders their characterization by a single method challenging. We have developed a comprehensive two-dimensional liquid chromatography method hyphenated with mass spectrometry and UV-vis detection.

Characterization of synthetic dyes by comprehensive two-dimensional liquid chromatography combining ion-exchange chromatography and fast ion-pair reversed-phase chromatography.

In the late 19th century, newly invented synthetic dyes rapidly replaced the natural dyes on the market. The characterization of mixtures of these so-called early synthetic dyes is complicated through the occurrence of many impurities and degradation products. Conventional one-dimensional liquid chromatography does not suffice to obtain fingerprints with sufficient resolution and baseline integrity.

High-performance liquid chromatography and non-destructive three-dimensional fluorescence analysis of early synthetic dyes.

Chromatographic and spectroscopic techniques are evaluated for the analysis of early synthetic dyes. The research focuses on the analysis of dyestuffs that were developed and used in the period 1850-1900, which has not been well investigated so far. The aim of this study was to develop and evaluate techniques that can be applied in the field of culture and art.