Secondary chemical equilibria in reversed-phase liquid chromatography

García-Álvarez-Coque, M.C.; Torres-Lapası́o, J.R.; Navarro-Huerta, J.A.

doi:10.1016/b978-0-12-805393-5.00005-1

Cited by 4 publications

(3 citation statements)

References 47 publications

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“…Micellar liquid chromatography (MLC) is a modified reverse-phase liquid chromatography approach in which a surfactant is used as a mobile phase (MP) modifier above its critical micellar concentration (CMC). The various equilibria, involving the partitioning of the solute with the aqueous phase, the micellar phase and the surfactant-coated stationary phase, are well known [1]. The role of surfactants in analytical chemistry, particularly chromatography, has been reviewed recently [2].…”

Section: Introductionmentioning

confidence: 99%

Ultra-High-Performance Micellar Liquid Chromatography Comparing Tween 20 and Tween 40 for the Determination of Hydroxycinnamic Acids

Ali

Danielson

2022

Separations

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A simple and green ultra-high-performance micellar liquid chromatography (MLC) method was developed here, comparing Tween 20 and Tween 40 for the first time as the only mobile phase modifiers with a C18 column. Its application to the separation of nine hydroxycinnamic acid (HCA) derivatives (cinnamic, caffeic, ferulic, sinapic, o-, m-, p-coumaric, 3,4-dihydroxyhydrocinnamic, and chlorogenic acids) was made, due to their importance as antioxidants in a variety of natural beverages such as wine and coffee. The optimal conditions of 45 °C temperature (T), 1% surfactant in the mobile phase, and pH control with 2.5 mM sulfuric acid were determined and used to elucidate the analytical figures of merit. Although the effect of these conditions was insignificant between the two surfactants, the nine-component HCA mixture was separated faster—in about 15 min—and with less peak tailing using Tween 20 than with Tween 40. The linearity of the Van’t Hoff (lnk versus 1/T) plots was evident for Tween 20, indicating a single retention mechanism—but less so for Tween 40. The equilibrium constants of the analytes with the micelles and the stationary phase were calculated. The developed method was successfully used to analyze organic red wine, spiked organic red wine, and green coffee diet pills. The percent recoveries of the nine HCA compounds spiked in the organic red wine ranged from 90% to 107%. The green coffee extract diet pills showed the presence of a significant amount of chlorogenic acid.

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Section: Introductionmentioning

confidence: 99%

Ultra-High-Performance Micellar Liquid Chromatography Comparing Tween 20 and Tween 40 for the Determination of Hydroxycinnamic Acids

Ali

Danielson

2022

Separations

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“…532 533 534 RPLC is very successful in the separation of a wide range of non-polar analytes. 535 However, polar and ionic compounds are not sufficiently retained on these columns unless ion 536 pairing reagents are added [15]. Common approaches to analyse samples comprising 537 compounds in a wide range of polarities make use of two or more columns in parallel, 538 involving different separation modes (e.g., RPLC, HILIC and/or ion exchange), or columns 539 using the same separation mode but rather different selectivity.…”

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confidence: 99%

“…6 stationary phases by a temporary or permanent modification, through the addition of additives 141 [15]. 142 The choice of stationary phase is crucial.…”

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confidence: 99%