## Abstract A polydimethylsiloxane (PDMS)โmodified monolithic silica column was prepared for performing reversedโphase capillary liquid chromatography. The prepared PDMS column has a permeability of 6.4ร10^โ14^โm^2^ with a plate height <9.2โฮผm. Alkylbenzenes and polycyclic aromatic hydrocarbons (PA
A trapping column for the coupling of reversed-phase liquid chromatography and capillary gas chromatography
โ Scribed by Vreuls, Jolan J. ;Goudriaan, Vincent P. ;Th, Udo A. ;de Jong, Gerhardus J.
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 611 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0935-6304
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โฆ Synopsis
Abstract
A new technique for coupling reversedโphase liquid chromatography (RPLC) with gas chromatography is described. A fraction eluting from an RPLC column is trapped on a short column packed with polymeric adsorbent. After the mobile phase has been displaced with water, the analytes are desorbed with ethyl acetate. Following a delay time to enable the water to be flushed to waste, the ethyl acetate containing the analytes is introduced into the gas chromatograph under conditions suitable for partially concurrent solvent evaporation, i.e. below the solvent boiling point and at a rate just exceeding the evaporation rate. Postโcolumn addition of water to the RPLC eluent helps to prevent breakthrough of compounds which are only modestly retained on the trapping column. The relationship between the capacity factors of the analytes on the trapping column and the required dilution factor is discussed. Polycyclic aromatic hydrocarbons are used as test compounds to study the system.
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Retention gaps with different polarity treatments were evaluated for reversed phase solvents. Aminopropyl-and cyanopropyldeactivated retention gaps showed the best results lor methanolwater mixtures. A reversed phase packed fused silica capillary LC column is connected on-line with a capillary gas c
The extract was filtered and the filtrate diluted with an equal volume of water. 50 ml strong solution of lead subacetate was added and the mixture centrifuged after 5 minutes. Excess lead was precipitated with 10% disodium hydrogen phosphate and the mixture again centrifuged. The supernatant was su
## Abstract An onโline reversedโphase LCโGC method involving the use of a Programmed Temperature Vaporizer (PTV) as interface is used for the rapid analysis of sterols. The experimental procedure requires only the use of commercial HPLC and GC equipments and a Rheodyne valve. The LC preseparation c