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Burk RJ, Wahab MF, Armstrong DW. Influence of theoretical and semi-empirical peak models on the efficiency calculation in chiral chromatography. Talanta 2024; 277:126308. [PMID: 38820823 DOI: 10.1016/j.talanta.2024.126308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/13/2024] [Accepted: 05/20/2024] [Indexed: 06/02/2024]
Abstract
Height equivalent to theoretical plate (H) equations, such as the van Deemter or Knox-Saleem equations, and other efficiency vs. linear velocity equations (u), provide kinetic insights into chromatographic separations phenomena and column performance. In enantioselective separations, the peak shape of the two enantiomers can differ significantly and are often asymmetric. The peak efficiency calculations heavily impact these efficiency-flow profiles, leading to erroneous estimations of eddy diffusion, longitudinal diffusion, and mass transfer terms. In this work, new asymmetric peak functions are employed for modeling enantiomer peaks based on the Haarhoff-Van der Linde function, its generalized variant (GHVL), once Generalized Asymmetric Gaussian (AGN), and Twice Generalized Gaussian (TGN). The new models (AGN, TGN, and GHVL) incorporate higher statistical moments besides the zeroth, first, and second moments to account for two-sided asymmetry (fronting or tailing). The fit results are compared with the traditional efficiency calculation methods endorsed by official pharmacopeia and numerical estimation of moments from the raw data. Enantiomeric separations of ibuprofen and dl-homophenylalanine were chosen as probe molecules. The results demonstrate that non-linear least squares fitted functions provide better estimations of peak efficiency data even in the presence of high noise. In particular, the generalized models consistently offered the best quality fits for various peak shapes in chiral separations. Conversely, the half-height Gaussian method greatly overpredicted skewed peak efficiencies. This investigation reveals that the commonly held assumptions of peak shape and numerical integration of raw data are highly insufficient for chiral chromatography. The impact of asymmetry on plate height should not be overlooked when accurate data from efficiency-flow rate curves is derived. We advocate for the broader adoption of these new generalized peak (AGN, TGN, GHVL) models because they provide robustness at various SNRs that account for right or left asymmetry while accurately representing peak geometry.
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Affiliation(s)
- Ryan Jacob Burk
- Department of Chemistry & Biochemistry, University of Texas at Arlington, Texas, 76019, USA
| | - M Farooq Wahab
- Department of Chemistry & Biochemistry, University of Texas at Arlington, Texas, 76019, USA.
| | - Daniel W Armstrong
- Department of Chemistry & Biochemistry, University of Texas at Arlington, Texas, 76019, USA.
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2
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Weise C, Fischer J, Belder D. Mass spectrometry coupling of chip-based supercritical fluid chromatography enabled by make-up flow-assisted backpressure regulation. Anal Bioanal Chem 2024; 416:4447-4456. [PMID: 38907770 PMCID: PMC11294422 DOI: 10.1007/s00216-024-05381-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 05/17/2024] [Accepted: 05/31/2024] [Indexed: 06/24/2024]
Abstract
This work introduces a novel microfluidic backpressure pressure control developed for chip-based supercritical fluid chromatography (chipSFC). The presented on-chip pressure control mechanism involves the post-column addition of a viscous make-up stream, which enables pressure regulation within the range of 73 to 130 bar range. In contrast to approaches using mechanical backpressure regulators, this chip-based make-up-assisted pressure regulation offers a wear-free alternative that functions entirely through fluidic means and contributes minimally to extra column volume. It prevents phase separation of the supercritical mobile phase and, therefore, expands the analytical scope of chipSFC to detection systems with an ambient pressure interface. This was demonstrated by a proof-of-principle experiment, where a model mixture was separated within 30 s and detected using atmospheric pressure ionisation mass spectrometry.
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Affiliation(s)
- Chris Weise
- Institute of Analytical Chemistry, University of Leipzig, Linnéstrasse 3, 04103, Leipzig, Germany
| | - Johannes Fischer
- Institute of Analytical Chemistry, University of Leipzig, Linnéstrasse 3, 04103, Leipzig, Germany
| | - Detlev Belder
- Institute of Analytical Chemistry, University of Leipzig, Linnéstrasse 3, 04103, Leipzig, Germany.
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3
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Peterle D, DePice D, Wales TE, Engen JR. Increase the flow rate and improve hydrogen deuterium exchange mass spectrometry. J Chromatogr A 2023; 1689:463742. [PMID: 36586285 PMCID: PMC9872520 DOI: 10.1016/j.chroma.2022.463742] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 12/15/2022] [Accepted: 12/21/2022] [Indexed: 12/24/2022]
Abstract
Reversed-phase peptide separation in hydrogen deuterium exchange (HDX) mass spectrometry (MS) must be done with conditions where the back exchange is the slowest possible, the so-called quench conditions of low pH and low temperature. To retain maximum deuterium, separation must also be done as quickly as possible. The low temperature (0 °C) of quench conditions complicates the separation and leads primarily to a reduction in separation quality and an increase in chromatographic backpressure. To improve the separation in HDX MS, one could use a longer gradient, smaller particles, a different separation mechanism (for example, capillary electrophoresis), or multi-dimensional separations such as combining ion mobility separation with reversed-phase separation. Another way to improve separations under HDX MS quench conditions is to use a higher flow rate where separation efficiency at 0 °C is more ideal. Higher flow rates, however, require chromatographic systems (both pumps and fittings) with higher backpressure limits. We tested what improvements could be realized with a commercial UPLC/UHPLC system capable of ∼20,000 psi backpressure. We found that a maximum flow rate of 225 µL/min (using a 1 × 50 mm column packed with 1.8 µm particles) was possible and that higher flow rate clearly led to higher peak capacity. HDX MS analysis of both simple and particularly complex samples improved, permitting both shorter separation time, if desired, and providing more deuterium recovery.
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Affiliation(s)
- Daniele Peterle
- Department of Chemistry and Chemical Biology, Northeastern University, Mailstop 412 TF, 360 Huntington Avenue, Boston, MA 02115, United States
| | - David DePice
- Department of Chemistry and Chemical Biology, Northeastern University, Mailstop 412 TF, 360 Huntington Avenue, Boston, MA 02115, United States
| | - Thomas E Wales
- Department of Chemistry and Chemical Biology, Northeastern University, Mailstop 412 TF, 360 Huntington Avenue, Boston, MA 02115, United States
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Mailstop 412 TF, 360 Huntington Avenue, Boston, MA 02115, United States.
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Aslani S, Wahab MF, Kenari ME, Berthod A, Armstrong DW. An examination of the effects of water on normal phase enantioseparations. Anal Chim Acta 2022; 1200:339608. [DOI: 10.1016/j.aca.2022.339608] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 11/28/2022]
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5
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Bennett R, Pirrone GF, Nowak T, Mukherjee D, Shchurik V, Mapelli C, Hickey JL, Regalado EL, Mangion I, Makarov AA. Ultra-high-throughput SPE-MALDI workflow: Blueprint for efficient purification and screening of peptide libraries. Anal Chim Acta 2021; 1142:10-18. [PMID: 33280687 DOI: 10.1016/j.aca.2020.10.045] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 12/30/2022]
Abstract
At the forefront of synthetic endeavors in the pharmaceutical industry, including drug discovery and high-throughput screening, timelines are tight and large quantities of pure chemical targets are rarely available. In this regard, the development of novel and increasingly challenging chemistries requires a commensurate level of innovation to develop reliable analytical assays and purification workflows with rapid turnaround that enables accelerated pharmacological evaluation. A small-scale automation platform enabling high-throughput analysis and purification to streamline the selection of candidate leads would be a transformative advance. Herein, we introduce an automation-friendly solid-phase extraction-matrix-assisted laser desorption/ionization (SPE-MALDI) platform applied to the high-throughput purification and analysis of peptide libraries. This advance enabled us to purify peptides from microgram levels in less than a day with results comparable to traditional high-performance liquid chromatography-diode array detection-mass spectrometry (HPLC-DAD-MS).
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Affiliation(s)
- Raffeal Bennett
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA.
| | - Gregory F Pirrone
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA.
| | - Timothy Nowak
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA
| | - Debopreeti Mukherjee
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA
| | - Vladimir Shchurik
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA
| | - Claudio Mapelli
- Merck & Co., Inc., MRL, Chemistry Capabilities for Accelerating Therapeutics, Discovery Chemistry, Kenilworth, NJ, 07033, USA
| | - Jennifer L Hickey
- Merck & Co., Inc., MRL, Chemistry Capabilities for Accelerating Therapeutics, Discovery Chemistry, Kenilworth, NJ, 07033, USA
| | - Erik L Regalado
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA.
| | - Ian Mangion
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA
| | - Alexey A Makarov
- Merck & Co., Inc., MRL, Analytical Research & Development, Rahway, NJ, 07065, USA
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Wahab MF, Roy D, Armstrong DW. The theory and practice of ultrafast liquid chromatography: A tutorial. Anal Chim Acta 2020; 1151:238170. [PMID: 33608081 DOI: 10.1016/j.aca.2020.12.045] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 12/20/2020] [Accepted: 12/22/2020] [Indexed: 11/30/2022]
Abstract
Modern high-throughput experimentation and challenging analytical problems of academic/industrial research have put the responsibility on separation scientists to develop new fast separation approaches. With the availability of high-pressure pumps, small particles with hydrolytically stable surface chemistries, reduced extra-column band broadening, and low volume detectors with fast signal processing, it is now feasible to do sub-minute to sub-second chromatography. Herein, the fundamental theoretical principles of ultrafast chromatography, along with practical solutions, are reviewed. Approaches for rapid separations in packed beds, narrow open tubular columns, and monoliths are demonstrated, along with the challenges that were faced. The instrumentation requirements (pumps, injection systems, detectors, column packing process) for using short columns ranging from 0.5 to 5 cm are examined, followed by real applications. One of the main problems in ultrafast chromatography is partial or complete peak overlap. As per Gidding's statistical overlap theory, peak overlap cannot be avoided for a completely random sample for a column with a given peak capacity. Signal processing techniques based on Fourier transform deconvolution of band broadening, power laws, derivatives, and iterative curve fitting are explained to help improve the chromatographic resolution. An example of ten peaks separated in under a second is shown and discussed. Other ultrafast separations in supercritical fluid chromatography or capillary electrophoresis are briefly mentioned to provide a complete understanding of this emerging field.
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Affiliation(s)
- M Farooq Wahab
- Department of Chemistry & Biochemistry, University of Texas at Arlington, TX, USA.
| | - Daipayan Roy
- Department of Chemistry & Biochemistry, University of Texas at Arlington, TX, USA
| | - Daniel W Armstrong
- Department of Chemistry & Biochemistry, University of Texas at Arlington, TX, USA.
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Comprehensive online multicolumn two-dimensional liquid chromatography-diode array detection-mass spectrometry workflow as a framework for chromatographic screening and analysis of new drug substances. Anal Bioanal Chem 2020; 412:2655-2663. [DOI: 10.1007/s00216-020-02498-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 01/24/2020] [Accepted: 02/07/2020] [Indexed: 01/05/2023]
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Kaplitz AS, Kresge GA, Selover B, Horvat L, Franklin EG, Godinho JM, Grinias KM, Foster SW, Davis JJ, Grinias JP. High-Throughput and Ultrafast Liquid Chromatography. Anal Chem 2019; 92:67-84. [DOI: 10.1021/acs.analchem.9b04713] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Alexander S. Kaplitz
- Department of Chemistry & Biochemistry, Rowan University, Glassboro, New Jersey 08028, United States
| | - Glenn A. Kresge
- Department of Chemistry & Biochemistry, Rowan University, Glassboro, New Jersey 08028, United States
| | - Benjamin Selover
- Department of Chemistry & Biochemistry, Rowan University, Glassboro, New Jersey 08028, United States
| | - Leah Horvat
- Department of Chemistry & Biochemistry, Rowan University, Glassboro, New Jersey 08028, United States
| | | | - Justin M. Godinho
- Advanced Materials Technology, Inc., Wilmington, Delaware 19810, United States
| | - Kaitlin M. Grinias
- Analytical Platforms & Platform Modernization, GlaxoSmithKline, Upper Providence, Collegeville, Pennsylvania 19426, United States
| | - Samuel W. Foster
- Department of Chemistry & Biochemistry, Rowan University, Glassboro, New Jersey 08028, United States
| | - Joshua J. Davis
- Department of Chemistry & Biochemistry, Rowan University, Glassboro, New Jersey 08028, United States
| | - James P. Grinias
- Department of Chemistry & Biochemistry, Rowan University, Glassboro, New Jersey 08028, United States
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Vera C, Samuelsson J, Fornstedt T, Dennis G, Shalliker R. Protocol for the visualisation of axial temperature gradients in ultra high performance liquid chromatography using infrared cameras. Microchem J 2018. [DOI: 10.1016/j.microc.2018.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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10
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Lambert N, Felinger A. The effect of the frictional heat on retention and efficiency in thermostated or insulated chromatographic columns packed with sub-2-μm particles. J Chromatogr A 2018; 1565:89-95. [DOI: 10.1016/j.chroma.2018.06.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/11/2018] [Accepted: 06/16/2018] [Indexed: 11/28/2022]
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