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Separations
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Advances in High Pressure Liquid Chromatography
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Advances in High Pressure Liquid Chromatography

A special issue of Separations (ISSN 2297-8739).

Deadline for manuscript submissions: closed (28 February 2017) | Viewed by 27061

Special Issue Editor

Prof. Dr. Michael J. Dunphy

E-Mail Website
Guest Editor
Division of Mathematics and Sciences, Walsh University, OH, USA
Interests: analytical biochemistry; HPLC; GLC; TLC and method development for small molecule analysis

Special Issue Information

Dear Colleagues,

High Pressure Liquid Chromatography (HPLC, UHPLC) has become one of the most useful methods worldwide for the separation and analysis of mixtures and the verification of purity of synthetic materials among other applications. The ongoing evolution of HPLC has included advances in components such as column types and composition, solvent delivery systems, detection systems, data handling systems, and, of course, sample preparation. The usual goal is to achieve excellent compound resolution in a reasonable time with appropriate detection limits, and low costs with high throughput when needed. This Special Issue is focused on making the latest research and advancements in HPLC/UHPLC technology and applications available to readers. The issue invites contributions related to, but not limited to, column packing technology, system component variations to improve HPLC/UHPLC performance and the application of HPLC/UHPLC methods to a solve challenging separation and/or quantitation problems.

Prof. Dr. Michael J. Dunphy
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Separations is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.


Keywords

  • optimizing resolution
  • solid phase materials
  • particle size
  • UHPLC
  • theoretical plates
  • mobile phase optimization

Published Papers (4 papers)

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Research

1142 KiB  
Article
Determination of Carotenoids in Human Serum and Breast Milk Using High Performance Liquid Chromatography Coupled with a Diode Array Detector (HPLC-DAD)
by Jing Tan, Jason Gek Leong Neo, Tania Setiawati and Chunyan Zhang
Separations 2017, 4(2), 19; https://doi.org/10.3390/separations4020019 - 17 May 2017
Cited by 6 | Viewed by 6933
Abstract
High performance liquid chromatography (HPLC) coupled with a diode array detector (HPLC-DAD) for the identification and quantification of carotenoids, namely all-trans lutein, zeaxanthin, β-cryptoxanthin, α-carotene, and β-carotene, in biological samples such as human serum and breast milk, has been developed and validated. [...] Read more.
High performance liquid chromatography (HPLC) coupled with a diode array detector (HPLC-DAD) for the identification and quantification of carotenoids, namely all-trans lutein, zeaxanthin, β-cryptoxanthin, α-carotene, and β-carotene, in biological samples such as human serum and breast milk, has been developed and validated. Good chromatography separation was achieved using a binary mobile phase system on a YMC C30 column (150 × 2.1 mm, 3 µm) at 30 °C. Owing to the smaller column particle size and diameter of the column, the separation was achieved in 18 min, which is significantly reduced from the typical 30–40 min of other methods. The diode array detector (DAD) acquisition was set at a wavelength of 445 nm; 3D spectra ranging from wavelengths of 240–600 nm were also recorded. Peaks were identified by matching their retention time and spectra with those of standards. Quantification was achieved by internal standard calibration using echinenone as the internal standard. Good linearity was obtained for each compound (R2 > 0.9999). The method quantification limits (MQLs) for serum and breast milk were 10 ng/mL and 5 ng/mL, in matrix, respectively. A spike recovery study and standard reference material (SRM) from the National Institute of Standards and Technology (NIST) 968e analysis has proven that the method has a high degree of accuracy, precision, and robustness. The stability study showed that the carotenoid standard and sample extracts could be stored in a chilled autosampler at 8 °C up to 48 h without being comprised, which provides guidance on re-test time frames. The freeze/thaw process was found to be detrimental to carotenoids, and should always be avoided. Most importantly, UV standardization of the stock standard is to be performed prior to each assay, and simply taking the values on Certificate of Analysis (CoA) for calculation of the standard concentration is not recommended. Full article
(This article belongs to the Special Issue Advances in High Pressure Liquid Chromatography)
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999 KiB  
Article
Liquid Chromatography Tandem Mass Spectrometry Analysis of Synthetic Coccidiostats in Eggs
by Francesca Buiarelli, Patrizia Di Filippo, Carmela Riccardi, Donatella Pomata, Luigi Giannetti, Bruno Neri and Daniela Rago
Separations 2017, 4(2), 15; https://doi.org/10.3390/separations4020015 - 17 Apr 2017
Cited by 11 | Viewed by 4583
Abstract
Coccidiostats are synthetic drugs administered to animals, especially to poultry, to cure coccidiosis. In this paper, we present a selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze residues of five synthetic coccidiostats in eggs: clazuril, diclazuril, robenidine, nicarbazin, toltrazuril and its two [...] Read more.
Coccidiostats are synthetic drugs administered to animals, especially to poultry, to cure coccidiosis. In this paper, we present a selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze residues of five synthetic coccidiostats in eggs: clazuril, diclazuril, robenidine, nicarbazin, toltrazuril and its two metabolites. The extraction efficiency was evaluated by testing several solvents, pH, different volumes and time of extraction. The clean-up procedures were optimized using different solid phase extraction cartridges and different eluants. The chromatographic separation was achieved in reversed phase using a gradient of 0.1% formic acid in water and acetonitrile, whereas the MS detection was performed in negative electrospray ionization (ESI) for all the analytes, except for the robenidine. The developed method has been validated according to Commission Decision 2002/657/CE. The validation parameters, as linearity, precision, recovery, specificity, decision limit (CCα), detection capability (CCβ), and robustness have been determined. The proposed method resulted simple, fast, and suitable for screening and confirmation purposes. Full article
(This article belongs to the Special Issue Advances in High Pressure Liquid Chromatography)
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2610 KiB  
Communication
Low-Temperature Mobile Phase for Peptide Trapping at Elevated Separation Temperature Prior to Nano RP-HPLC-MS/MS
by Matthias Schöbinger, Oskar-James Klein and Goran Mitulović
Separations 2016, 3(1), 6; https://doi.org/10.3390/chromatography3010006 - 04 Feb 2016
Cited by 11 | Viewed by 6384
Abstract
Nano HPLC-MS/MS separation and detection of peptides for proteomic analysis is usually performed upon tryptic digest of proteins and peptide pre-concentration on trap columns. Pre-concentration on trap columns is needed for sample wash (removal of salts and impurities), sample focusing prior to separation, [...] Read more.
Nano HPLC-MS/MS separation and detection of peptides for proteomic analysis is usually performed upon tryptic digest of proteins and peptide pre-concentration on trap columns. Pre-concentration on trap columns is needed for sample wash (removal of salts and impurities), sample focusing prior to separation, and volume reduction. Usually, trap columns are mounted on selection valves close to the separation column in order to keep the void volume low and to enable injection of large sample amounts onto nano-separation column. Since separation columns are operated at elevated temperature of ≥45 °C and they are mounted on the same valve as the trap column (in the column oven); loading samples at elevated temperature will result with significant loss of analytes. A method for loading samples on a trap column at 60 °C was developed and optimized. No sample loss was observed when the optimized method was used for analysis of standards and of complex biological samples. Full article
(This article belongs to the Special Issue Advances in High Pressure Liquid Chromatography)
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2577 KiB  
Article
Measurement and Modeling of Extra-Column Effects Due to Injection and Connections in Capillary Liquid Chromatography
by James P. Grinias, Bernard Bunner, Martin Gilar and James W. Jorgenson
Chromatography 2015, 2(4), 669-690; https://doi.org/10.3390/chromatography2040669 - 01 Dec 2015
Cited by 29 | Viewed by 8207
Abstract
As column volumes continue to decrease, extra-column band broadening has become an increasingly important consideration when determining column performance. Combined contributions due to the injector and connecting tubing in a capillary LC system were measured and found to be larger than expected by [...] Read more.
As column volumes continue to decrease, extra-column band broadening has become an increasingly important consideration when determining column performance. Combined contributions due to the injector and connecting tubing in a capillary LC system were measured and found to be larger than expected by Taylor-Aris theory. Variance from sigma-type and tau-type broadening was isolated from eluted peaks using the Foley-Dorsey Exponentially Modified Gaussian peak fitting model and confirmed with computational fluid dynamics. It was found that the tau-type contributions were the main cause for the excessive broadening because of poorly-swept volumes at the connection between the injector and tubing. To reduce tau-type contributions (and peak tailing), a timed pinch mode could be used for analyte injection. Full article
(This article belongs to the Special Issue Advances in High Pressure Liquid Chromatography)
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