Retention times and bandwidths in reversed-phase gradient liquid chromatography of peptides and proteins

2011 ◽  
Vol 1218 (49) ◽  
pp. 8874-8889 ◽  
Author(s):  
Pavel Jandera ◽  
Zdeňka Kučerová ◽  
Jiří Urban
Keyword(s):  
Liquid Chromatography ◽  
Reversed Phase ◽  
Phase Gradient ◽  
Gradient Liquid Chromatography

scholarly journals Separation of Poly(styrene-block-t-butyl methacrylate) Copolymers by Various Liquid Chromatography Techniques

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Tina Šmigovec Ljubič ◽  
David Pahovnik ◽  
Majda Žigon ◽  
Ema Žagar
Keyword(s):  
Liquid Chromatography ◽  
Block Copolymers ◽  
Molar Mass ◽  
Small Difference ◽  
Reversed Phase ◽  
Butyl Methacrylate ◽  
Critical Conditions ◽  
Chromatographic Techniques ◽  
Methacrylate Copolymers ◽  
Gradient Liquid Chromatography

The separation of a mixture of three poly(styrene-block-t-butyl methacrylate) copolymers (PS-b-PtBMA), consisting of polystyrene (PS) blocks of similar length andt-butyl methacrylate (PtBMA) blocks of different lengths, was performed using various chromatographic techniques, that is, a gradient liquid chromatography on reversed-phase (C18 and C8) and normal-phase columns, a liquid chromatography under critical conditions for polystyrene as well as a fully automated two-dimensional liquid chromatography that separates block copolymers by chemical composition in the first dimension and by molar mass in the second dimension. The results show that a partial separation of the mixture of PS-b-PtBMA copolymers can be achieved only by gradient liquid chromatography on reversed-phase columns. The coelution of the two block copolymers is ascribed to a much shorter PtBMA block length, compared to the PS block, as well as a small difference in the length of the PtBMA block in two of these copolymers, which was confirmed by SEC-MALS and NMR spectroscopy.

EVIDENCE FOR BIIIARY EXCRETION OF PHENPROCOUMON AND ITS METABOLITES IN HUMANS; IDENTIFICATION BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY AND GAS CHROMATOGRAPHY-MASS SPECTROMETRY

1987 ◽  
Author(s):  
J X de Vries ◽  
R Raedsch ◽  
A Stiehl ◽  
U Voelker ◽  
I Walter-Sack ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Gas Chromatography Mass Spectrometry ◽  
Phase Gradient ◽  
Chromatography Mass Spectrometry

Recently it has been shown that in man the oral couma-rin anticoagulant phenprocoumon is eliminated up to 60-70 % in urine and 30-40 % in faeces; in urine phenprocoumon (PH) and its metabolites 7-hydroxy-(7-OH),6-hydroxy-(6-OH) and 4'-hydroxy-(4'-OH) phenprocoumon are present mainly as conjugates. No data so far were available on the biliary excretion of these compounds.We examined bile obtained from four in-patients during PH treatment; bile samples were aspirated in the duodenum at the papilla during routine diagnostic endoscopy and immediately deep frozen before analysis. Samples were extracted both untreated as well as after hydrolysis with 6-glucuronidase/aryl sulfatase and separated by reversed phase gradient elution high performance liquid chromatography (HPLC) with fluorescence detection; for confirmation, the same extracts were methylated and analysed by gas chromatography-mass spectrometry (CG-MS) (J.X.de Vries et al J Chromatogr., 338 (1985) 325). PH, 7-OH, 6-OH and 4'-OH were identified by comparison with synthetic authentic samples'''''''

scholarly journals Separation of porphyrin isomers by high-performance liquid chromatography

1983 ◽  
Vol 211 (2) ◽  
pp. 435-438 ◽  
Author(s):  
C K Lim ◽  
J M Rideout ◽  
D J Wright
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
High Performance ◽  
Gradient Elution ◽  
Reversed Phase ◽  
Type I ◽  
Phase Gradient ◽  
Preparative Isolation ◽  
Type Iii ◽  
Simultaneous Separation

A reversed-phase gradient elution system is described for the simultaneous separation of the type I and type III isomers of 8-, 7-, 6-, 5- and 4-carboxylated porphyrins and isocoproporphyrins. The method, adaptable for isocratic and stepwise separation of individual groups of isomers, is also suitable for preparative isolation of pure porphyrins. The analyses of porphyrin isomers in the urine and faeces of porphyric patients are examples of applications.

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