Limited sample recovery in coupled methods of high-performance liquid chromatography of synthetic polymers

2006 ◽  
Vol 60 (3) ◽  
Author(s):  
D. Berek ◽  
A. Russ
Keyword(s):  
Liquid Chromatography ◽  
High Performance ◽  
Retention Mechanism ◽  
Model Systems ◽  
Critical Conditions ◽  
Chromatographic Methods ◽  
Enthalpic Interaction ◽  
Sample Recovery ◽  
Gradient Liquid Chromatography ◽  
Liquid Chromatographic

AbstractComplex polymer systems, which exhibit multiple distributions in their molecular parameters can be characterized by coupled liquid chromatographic methods. The latter combine entropic (exclusion) and enthalpic (interaction) retention mechanisms. However, recent experimental results suggest that some coupled liquid chromatographic methods may suffer from incomplete sample recovery. This refers, for example, to liquid chromatography under critical conditions of enthalpic interactions and to eluent gradient liquid chromatography. Sample recovery in both latter methods was investigated for selected model systems applying adsorption retention mechanism. Reduced sample recovery was confirmed for both methods. It was revealed that even very high final strength of mobile phase may be insufficient for complete elution of polymer samples in eluent gradient polymer liquid chromatography.

scholarly journals Bioanalysis of aminoglycosides using high-performance liquid chromatography

ADMET & DMPK ◽  
2022 ◽  
Author(s):  
Seth K. Amponsah ◽  
Joseph A. Boadu ◽  
Daniel K. Dwamena ◽  
Kwabena F.M. Opuni
Keyword(s):  
Liquid Chromatography ◽  
Bacterial Infections ◽  
High Performance ◽  
Relevant Literature ◽  
Therapeutic Index ◽  
Reversed Phase ◽  
Detection Methods ◽  
Intermediate Precision ◽  
Chromatographic Methods ◽  
Liquid Chromatographic

Aminoglycosides are broad-spectrum antibiotics used in the treatment of gram-negative bacterial infections. Due to their nephrotoxic and ototoxic potential (narrow therapeutic index), the use of aminoglycoside for clinical indications requires monitoring. The objective of this review was to identify relevant literature reporting liquid chromatographic methods for the bioanalysis of aminoglycosides in both preclinical and clinical settings/experiments. Data on liquid chromatographic methods were collected from articles in an online academic database (PubMed, Science Direct, Scopus, and Google Scholar). All 71 articles published from 1977 to 2020 were included in the review. Reversed-phase liquid chromatography was the most used method for the bioanalysis of aminoglycosides. Fluorescence or ultraviolet detection methods were mostly used from 1977 to 2002 (51 articles), while mass spectrometry was predominantly used as a detector from 2003 to 2020 (15 articles). Sixty-seven articles reported calibration ranges, which varied significantly for the various drugs assayed: some in the range of 0.1-0.5 ng/mL and others 1250-200000 ng/mL. Also, 61 articles reported R2 values (0.964-1.0) for almost all analytes under consideration. Sixty-three articles reported percent recoveries mostly between 61.0 % to 114.0 %, with only two articles reporting recoveries of 4.9 % and 36 %. Out of the 71 reviewed articles, 56 reported intermediate precision values ranging between 0.331 % to 19.76 %, which is within the acceptable limit of 20 %. This review will serve as a guide for research and/or routine clinical monitoring of aminoglycosides in biological matrices.

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.

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