Quantitative two-dimensional thin-layer chromatography using a diode-array detector

Abstract

AbstraktWir präsentieren die weltweit erste Auswertung einer zweidimensional entwickelten HPTLC-Platte (2D-HPTLC) mit Hilfe eines Diodenarray-Scanners. Das System erreicht eine räumliche Plattenauflösung von 250 µm. Es können Absorptions-und Fluoreszenzspektren im Wellenlängenbereich von 190 bis 1000 nm mit einer spektralen Auflösung von besser als 1 nm gemessen werden. Eine Trennzahl von 259 wurde erreicht. Damit zeigt die Methode bessere Trenneigenschaften als die meisten HPLC-Systeme. Der Nachteil der 2D-Auswertung ist der hohe Zeitbedarf von über 3 Stunden für eine Plattenmessung.

Planar Electrochromatography Using an Electrospun Polymer Nanofiber Layer

“…2D chromatography results in increased SN values which are critical in the separation of complex mixtures; the significance is rooted in the selectivity difference of the two dimensions. If the retention mechanisms are truly orthogonal, SN of the 2D separation ( SN 2D ) is expected to be SN 1 × SN 2 , where SN 1 and SN 2 correspond to the first and second dimensions, respectively . Typically, analytes are spotted at the bottom corner of a plate and developed in the first dimension.…”

“…If the retention mechanisms are truly orthogonal, SN of the 2D separation (SN 2D ) is expected to be SN 1 × SN 2 , where SN 1 and SN 2 correspond to the first and second dimensions, respectively. 44 Typically, analytes are spotted at the bottom corner of a plate and developed in the first dimension. After drying, the same plate is turned 90°for development in the second dimension using a different mobile phase for diverse selectivity.…”

Instrument platforms for thin-layer chromatography

“…[69]. A reflection attachment made of nine identical 100 m diameter optical fibers for illumination arranged in a circle around a single 200 m diameter optical fiber for collection of reflected light was used for scanning two-dimensional separations, but complete scanning of a single sample is a slow process (hours per separation) [70].…”

Milestones, Core Concepts, and Contrasts

“…A common arrangement is the use of normal-phase and reversed-phase solvent systems on a polar chemically bonded stationary phase. One barrier, the recording of two-dimensional chromatograms, has largely been solved using videodensitometry, photodiode array detection, or mass spectrometric detection [15,52,53]. The use of reversed-phase conditions with a silica gel stationary phase or a bilayer plate with a strip of chemically bonded stationary phase butted against a larger strip of silica gel is complicated by alteration of the stationary phase properties by the mobile phase employed for the first development.…”