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de Paula Lima I, Polycarpo Valle S, de Oliveira MAL, de Carvalho Marques FF, Antonio Simas Vaz F. Monolithic stationary phases preparation for use in chromatographic and electromigration techniques: the state-of-the-art. Microchem J 2023. [DOI: 10.1016/j.microc.2023.108598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
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2
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Svobodová J, Mikšík I. Open-tubular capillary electrochromatographic application of a sol-gel matrix with chilli peppers, garlic, or synthetic additives. J Sep Sci 2020; 43:3691-3701. [PMID: 32662597 DOI: 10.1002/jssc.202000515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/09/2020] [Accepted: 07/09/2020] [Indexed: 11/07/2022]
Abstract
This article describes a possible combination of two promising fields of analytical chemistry-the preparation of sol-gel matrices with varying additives and their application in capillary electrochromatography. The inner surfaces of capillaries were coated with the sol-gel solution containing either pure synthetic chemical additive-alliin or capsaicin-or an extract of their natural sources-garlic and chilli pepper, respectively. The modified capillaries were tested for interaction with two neurotransmitters, oligopeptides and nucleotides under conditions of open-tubular capillary electrochromatography. Because both of the natural extracts also contain vitamin C and saccharose, the capillaries with sol-gel modifiers containing each of these substances were also tested. The obtained results from the perspective of changes in the electrochromatograms and the effective mobilities of analytes are discussed with respect to mild conditions both in the preparation process of the sol-gel matrix and during the separations.
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Affiliation(s)
- Jana Svobodová
- Department of Translation Metabolism, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ivan Mikšík
- Department of Translation Metabolism, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic
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A Dual Ligand Sol⁻Gel Organic-Silica Hybrid Monolithic Capillary for In-Tube SPME-MS/MS to Determine Amino Acids in Plasma Samples. Molecules 2019; 24:molecules24091658. [PMID: 31035579 PMCID: PMC6540176 DOI: 10.3390/molecules24091658] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/17/2019] [Accepted: 04/24/2019] [Indexed: 11/17/2022] Open
Abstract
This work describes the direct coupling of the in-tube solid-phase microextraction (in-tube SPME) technique to a tandem mass spectrometry system (MS/MS) to determine amino acids (AA) and neurotransmitters (NT) (alanine, serine, isoleucine, leucine, aspartic acid, glutamic acid, lysine, methionine, tyrosine, and tryptophan) in plasma samples from schizophrenic patients. An innovative organic-silica hybrid monolithic capillary with bifunctional groups (amino and cyano) was developed and evaluated as an extraction device for in-tube SPME. The morphological and structural aspects of the monolithic phase were evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), nitrogen sorption experiments, X-ray diffraction (XRD) analyses, and adsorption experiments. In-tube SPME-MS/MS conditions were established to remove matrix, enrich analytes (monolithic capillary) and improve the sensitivity of the MS/MS system. The proposed method was linear from 45 to 360 ng mL-1 for alanine, from 15 to 300 ng mL-1 for leucine and isoleucine, from 12 to 102 ng mL-1 for methionine, from 10 to 102 ng mL-1 for tyrosine, from 9 to 96 ng mL-1 for tryptophan, from 12 to 210 ng mL-1 for serine, from 12 to 90 ng mL-1 for glutamic acid, from 12 to 102 ng mL-1 for lysine, and from 6 to 36 ng mL-1 for aspartic acid. The precision of intra-assays and inter-assays presented CV values ranged from 1.6% to 14.0%. The accuracy of intra-assays and inter-assays presented RSE values from -11.0% to 13.8%, with the exception of the lower limit of quantification (LLOQ) values. The in-tube SPME-MS/MS method was successfully applied to determine the target AA and NT in plasma samples from schizophrenic patients.
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Svobodová J, Kofroňová O, Benada O, Král V, Mikšík I. Separation of oligopeptides, nucleobases, nucleosides and nucleotides using capillary electrophoresis/electrochromatography with sol-gel modified inner capillary wall. J Chromatogr A 2017; 1517:185-194. [PMID: 28851524 DOI: 10.1016/j.chroma.2017.08.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 08/02/2017] [Accepted: 08/05/2017] [Indexed: 10/19/2022]
Abstract
The aim of this article is to study the modification of an inner capillary wall with sol-gel coating (pure silica sol-gel or silica sol-gel containing porphyrin-brucine conjugate) and determine its influence on the separation process using capillary electrophoresis/electrochromatography method. After modification of the inner capillary surface the separation of analytes was performed using two different phosphate buffers (pH 2.5 and 9.0) and finally the changes in electrophoretic mobilities of various samples were calculated. To confirm that the modification of the inner capillary surface was successful, the parts of the inner surfaces of capillaries were observed using scanning electron microscopy. The analytes used as testing samples were oligopeptides, nucleosides, nucleobases and finally nucleotides.
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Affiliation(s)
- Jana Svobodová
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
| | - Olga Kofroňová
- Laboratory of Molecular Structure Characterization, Institute of Microbiology, v.v.i., Czech Academy of Sciences, Prague, Czech Republic
| | - Oldřich Benada
- Laboratory of Molecular Structure Characterization, Institute of Microbiology, v.v.i., Czech Academy of Sciences, Prague, Czech Republic
| | - Vladimír Král
- Department of Analytical Chemistry, Institute of Chemical Technology, Prague, Czech Republic
| | - Ivan Mikšík
- Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic
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Preparation of organic-silica hybrid monolithic columns via crosslinking of functionalized mesoporous carbon nanoparticles for capillary liquid chromatography. J Chromatogr A 2017; 1498:64-71. [DOI: 10.1016/j.chroma.2017.03.067] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 11/22/2022]
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6
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Mikšík I. Capillary electrochromatography of proteins and peptides (2006-2015). J Sep Sci 2016; 40:251-271. [DOI: 10.1002/jssc.201600908] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 10/01/2016] [Accepted: 10/01/2016] [Indexed: 01/14/2023]
Affiliation(s)
- Ivan Mikšík
- Institute of Physiology; Academy of Sciences of the Czech Republic; Prague Czech Republic
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7
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Hu B, He M, Chen B, Jiang Z. Separation/Preconcentration Techniques for Rare Earth Elements Analysis. PHYSICAL SCIENCES REVIEWS 2016. [DOI: 10.1515/psr-2016-0056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The main aim of this chapter exactly characterizes the contribution. The analytical chemistry of the rare earth elements (REEs) very often is highly complicated and the determination of a specific element is impossible without a sample pre-concentration. Sample preparation can be carried out either by separation of the REEs from the matrix or by concentrating the REEs. The separation of REEs from each other is mainly made by chromatography.
At the beginning of REE analysis, the method of precipitation/coprecipitation was applied for the treatment of REE mixtures. The method is not applicable for the separation of trace amounts of REEs. The majority of the methods used are based on the distribution of REEs in a two-phase system, a liquid–liquid or a liquid–solid system. Various techniques have been developed for the liquid–liquid extraction (LLE), in particular the liquid phase micro-extraction. The extraction is always combined with a pre-concentration of the REEs in a single drop of extractant or in a hollow fiber filled with the extractant. Further modified techniques for special applications and for difficult REE separation have been developed. Compared to the LLE, the solid phase micro-extraction is preferred. The method is robust and easy to handle, in which the solid phase loaded with the REEs can be used directly for subsequent determination methods. At present, very new solid materials, like nanotubes, are developed and tested for solid phase extraction.
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One-Pot Approach to Prepare Organo-silica Hybrid Capillary Monolithic Column with Intact Mesoporous Silica Nanoparticle as Building Block. Sci Rep 2016; 6:34718. [PMID: 27698475 PMCID: PMC5048148 DOI: 10.1038/srep34718] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/19/2016] [Indexed: 11/08/2022] Open
Abstract
A facile "one-pot" approach to prepare organo-silica hybrid capillary monolithic column with intact mesoporous silica nanoparticle (IMSN) as crosslinker and building block was described. An IMSN crosslinked octadecyl-silica hybrid capillary monolithic column (IMSN-C18 monolithic column) was successfully prepared, and the effects of fabrication conditions (e.g. concentration of intact mesoporous silica nanoparticle, polycondensation temperature, content of vinyltrimethoxysilane and stearyl methacrylate) on the structures of the IMSN-C18 monolithic column were studied in detail. The IMSN-C18 hybrid monolithic column possessed uniform morphology, good mechanical and pH stability (pH 1.1-11), which was applied to the separations of alkyl benzenes, polycyclic aromatic hydrocarbons (PAHs), as well as proteins. The minimum plate height of 10.5 μm (corresponding to 95000 N m-1) for butylbenzene and high reproducibility were achieved. The analysis of tryptic digest of bovine serum albumin (BSA) was carried out on the IMSN-C18 monolithic column by cLC coupled mass spectrometry (cLC-MS/MS), with the protein sequence coverage of 87.5% for BSA, demonstrating its potential application in proteomics.
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Enantioseparations in open-tubular capillary electrochromatography: Recent advances and applications. J Chromatogr A 2016; 1467:145-154. [PMID: 27461922 DOI: 10.1016/j.chroma.2016.07.039] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 07/14/2016] [Accepted: 07/15/2016] [Indexed: 12/25/2022]
Abstract
This review highlights recent advances and applications in open-tubular capillary electrochromatography (OT-CEC) for enantioseparations during the last decade. Although extensive research has been conducted in the area of separations by use of CEC, and a big number of reviews have been published, there is not a review on exclusively the use of chiral stationary phases (CSPs) in OT-CEC for enantioseparations. Therefore, in this review, the design and synthesis of different CSPs are presented, and their potential applications in OT-CEC for enantioseparations are discussed. The different approaches to CSP development include chiral nanomaterials, porous layers, molecular imprinting, sol-gel technique, polyelectrolyte multilayer coating, polymeric coating and others.
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Domingues DS, Souza IDD, Queiroz MEC. Analysis of drugs in plasma samples from schizophrenic patients by column-switching liquid chromatography-tandem mass spectrometry with organic-inorganic hybrid cyanopropyl monolithic column. J Chromatogr B Analyt Technol Biomed Life Sci 2015; 993-994:26-35. [PMID: 25984963 DOI: 10.1016/j.jchromb.2015.04.040] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/24/2015] [Accepted: 04/26/2015] [Indexed: 10/23/2022]
Abstract
This study reports on the development of a rapid, selective, and sensitive column-switching liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze sixteen drugs (antidepressants, anticonvulsants, anxiolytics, and antipsychotics) in plasma samples from schizophrenic patients. The developed organic-inorganic hybrid monolithic column with cyanopropyl groups was used for the first dimension of the column-switching arrangement. This arrangement enabled online pre-concentration of the drugs (monolithic column) and their subsequent analytical separation on an XSelect SCH C18 column. The drugs were detected on a triple quadrupole tandem mass spectrometer (multiple reactions monitoring mode) with an electrospray ionization source in the positive ion mode. The developed method afforded adequate linearity for the sixteen target drugs; the coefficients of determination (R(2)) lay above 0.9932, the interassay precision had coefficients of variation lower than 6.5%, and the relative standard error values of the accuracy ranged from -14.0 to 11.8%. The lower limits of quantification in plasma samples ranged from 63 to 1250pgmL(-1). The developed method successfully analyzed the target drugs in plasma samples from schizophrenic patients for therapeutic drug monitoring (TDM).
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Affiliation(s)
- Diego Soares Domingues
- Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Brazil
| | - Israel Donizeti de Souza
- Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Brazil
| | - Maria Eugênia Costa Queiroz
- Departamento de Química, Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Brazil.
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Szumski M, Buszewski B. Preparation of Monolithic Capillary Chromatographic Columns Using Supercritical Fluid as a Porogen Solvent. Chromatographia 2014; 77:1009-1017. [PMID: 25089047 PMCID: PMC4111859 DOI: 10.1007/s10337-014-2651-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 02/24/2014] [Indexed: 11/09/2022]
Abstract
Monolithic polymeric beds were synthesized in fused silica capillaries using either trimethylolpropane trimethacrylate (TRIM) or a mixture of butyl methacrylate (BMA) with ethylene glycol dimethacrylate (EDMA) as monomers. Carbon dioxide at temperature and pressure conditions above its critical values was used as a porogen solvent. The purpose of using the supercritical carbon dioxide was to have the possibility of changing the solvation power (and thus the porosity of the resulting monolith) of the porogen by pressure and temperature changes instead of changing the porogen composition. The experiments were performed using a special setup consisting of a stainless steel high-pressure reactor to which the fused silica capillary was connected. The synthesized monoliths underwent liquid chromatographic evaluation. The polyTRIM capillary monoliths were characterized by different permeability, which depended on the pressure of the synthesis. BMA/EDMA columns were applied for separation of alkylbenzenes and a model mixture of proteins.
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Affiliation(s)
- Michał Szumski
- Faculty of Chemistry, Department of Environmental Chemistry and Bioanalytics, Nicolaus Copernicus University, Gagarina 7, 87-100 Toruń, Poland
| | - Bogusław Buszewski
- Faculty of Chemistry, Department of Environmental Chemistry and Bioanalytics, Nicolaus Copernicus University, Gagarina 7, 87-100 Toruń, Poland
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Zhong J, Hao M, Li R, Bai L, Yang G. Preparation and characterization of poly(triallyl isocyanurate -co- trimethylolpropane triacrylate) monolith and its applications in the separation of small molecules by liquid chromatography. J Chromatogr A 2014; 1333:79-86. [DOI: 10.1016/j.chroma.2014.01.072] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/27/2014] [Accepted: 01/27/2014] [Indexed: 11/26/2022]
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13
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Chienthavorn O, Ramnut N, Subprasert P, Sasook A, Insuan W. Effective and reusable monolith capillary trap of nitrosamine extraction by superheated water from frankfurter sausage. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:1240-1246. [PMID: 24437966 DOI: 10.1021/jf4036645] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A novel, simple, rapid, and inexpensive method of extraction and cleanup of nitrosamines from frankfurter sausage was achieved with a capillary filled with monolith of either polystyrene-co-divinylbenzene (PS-DVB), Polydivinylbenzene (P-DVB), or silica that had been fabricated. The study of capability in trapping nonpolar matrix and monolith capillaries with varied lengths revealed that a silica monolith gave the best result for nitrosamine determination. With an online coupling between superheated water extraction (SWE) and silica monolith capillary connected to a 5% phenyl-methylpolysiloxane column, factors affecting the extraction and determination, namely, sensitivity with and without the monolith, reusability, injection-injection repeatability, capillary-capillary precision, and chromatographic separation, were investigated. This confirmed the feasibility of the method. The optimal length of silica monolith capillary was 30 mm, offering reuse more than 20 times. Separation and quantification of selected volatile nitrosamines were carried out using gas chromatography (GC) coupled with either a flame ionization detector (FID) or mass spectrometer (MS). The overall extraction and determination method determined by GC-MS allowed for a recovery of 75-88% with a <5% relative standard deviation (RSD) and detection limit of 2-5 ng of injected nitrosamine.
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Affiliation(s)
- Orapin Chienthavorn
- Department of Chemistry and the Center of Excellence for Innovation in Chemistry, Faculty of Science, Kasetsart University , Post Office Box 1011, Chatuchak, Bangkok 10903, Thailand
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Attia S, Shames A, Zilbermann I, Goobes G, Maimon E, Meyerstein D. Covalent binding of a nickel macrocyclic complex to a silica support: towards an electron exchange column. Dalton Trans 2014; 43:103-10. [DOI: 10.1039/c3dt51962g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Tang S, Wang L, Han H, Qiu H, Liu X, Jiang S. Preparation and characterization of dipyridine modified hybrid-silica monolithic column for mixed-mode capillary electrochromatography. RSC Adv 2013. [DOI: 10.1039/c3ra40580j] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Lin Z, Huang H, Li S, Wang J, Tan X, Zhang L, Chen G. Preparation of phenylboronic acid-silica hybrid monolithic column with one-pot approach for capillary liquid chromatography of biomolecules. J Chromatogr A 2013; 1271:115-23. [DOI: 10.1016/j.chroma.2012.11.038] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 11/09/2012] [Accepted: 11/15/2012] [Indexed: 02/09/2023]
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Ou J, Zhang Z, Lin H, Dong J, Zou H. Polyhedral oligomeric silsesquioxanes as functional monomer to prepare hybrid monolithic columns for capillary electrochromatography and capillary liquid chromatography. Anal Chim Acta 2013; 761:209-16. [DOI: 10.1016/j.aca.2012.11.052] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Revised: 11/07/2012] [Accepted: 11/27/2012] [Indexed: 10/27/2022]
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Ou J, Lin H, Zhang Z, Huang G, Dong J, Zou H. Recent advances in preparation and application of hybrid organic-silica monolithic capillary columns. Electrophoresis 2012; 34:126-40. [PMID: 23161325 DOI: 10.1002/elps.201200344] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 10/13/2012] [Accepted: 10/13/2012] [Indexed: 01/19/2023]
Abstract
Hybrid organic-silica monolithic columns, regarded as a second generation of silica-based monoliths, have received much interest due to their unique properties over the pure silica-based monoliths. This review mainly focuses on development in the fields of preparation of hybrid monolithic columns in a capillary and their application for CEC and capillary liquid chromatography separation, as well as for sample pretreatment of solid-phase microextraction and immobilized enzyme reactor since July 2010. The preparation approaches are comprehensively summarized with three routes: (i) general sol-gel process using trialkoxysilanes and tetraalkoxysilanes as coprecursors; (ii) "one-pot" process of alkoxysilanes and organic monomers concomitantly proceeding sol-gel chemistry and free radical polymerization; and (iii) other polymerization approaches of organic monomers containing silanes. The modification of hybrid monoliths containing reactive groups to acquire the desired surface functionality is also described.
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Affiliation(s)
- Junjie Ou
- CAS Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R & A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
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Ou J, Lin H, Tang S, Zhang Z, Dong J, Zou H. Hybrid monolithic columns coated with cellulose tris(3,5-dimethylphenyl-carbamate) for enantioseparations in capillary electrochromatography and capillary liquid chromatography. J Chromatogr A 2012; 1269:372-8. [DOI: 10.1016/j.chroma.2012.09.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/29/2012] [Accepted: 09/04/2012] [Indexed: 10/27/2022]
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Electroneutral silica-based hybrid monolith for hydrophilic interaction capillary electrochromatography. J Chromatogr A 2012; 1260:174-82. [DOI: 10.1016/j.chroma.2012.08.053] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Revised: 08/14/2012] [Accepted: 08/16/2012] [Indexed: 11/24/2022]
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Wan L, Zhang L, Lei W, Zhu Y, Zhang W, Wang Y. Novel hybrid organic–inorganic monolithic column containing mesoporous nanoparticles for capillary electrochromatography. Talanta 2012; 98:277-81. [DOI: 10.1016/j.talanta.2012.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2012] [Revised: 06/27/2012] [Accepted: 07/01/2012] [Indexed: 11/30/2022]
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Ou J, Zhang Z, Lin H, Dong J, Wu M, Zou H. Preparation and application of hydrophobic hybrid monolithic columns containing polyhedral oligomeric silsesquioxanes for capillary electrochromatography. Electrophoresis 2012; 33:1660-8. [DOI: 10.1002/elps.201100566] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Junjie Ou
- CAS Key Laboratory of Separation Science for Analytical Chemistry; National Chromatographic R & A Center; Dalian Institute of Chemical Physics; Chinese Academy of Sciences (CAS); Dalian; China
| | | | | | - Jing Dong
- CAS Key Laboratory of Separation Science for Analytical Chemistry; National Chromatographic R & A Center; Dalian Institute of Chemical Physics; Chinese Academy of Sciences (CAS); Dalian; China
| | - Minghuo Wu
- CAS Key Laboratory of Separation Science for Analytical Chemistry; National Chromatographic R & A Center; Dalian Institute of Chemical Physics; Chinese Academy of Sciences (CAS); Dalian; China
| | - Hanfa Zou
- CAS Key Laboratory of Separation Science for Analytical Chemistry; National Chromatographic R & A Center; Dalian Institute of Chemical Physics; Chinese Academy of Sciences (CAS); Dalian; China
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Optimization of photo-polymerized sol–gel monolithic stationary phases prepared in polyacrylate-coated fused-silica capillaries for capillary electrochromatography. Microchem J 2012. [DOI: 10.1016/j.microc.2011.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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The Preparation and Characterization of Organic–Inorganic Hybrid Material Amino Monolithic Column for Capillary Electro Chromatography. ACTA ACUST UNITED AC 2011. [DOI: 10.4028/www.scientific.net/amm.130-134.410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper a novel hybrid organic–inorganic amino hybrid material monolithic column for capillary electro chromatography (CEC) is preparation and characterization. The amido hybrid material monolithic column was prepared in situ co-condensation of tetraethoxysilane (TEOS) with 3-aminoproplytriethoxysilane (3-APTES) via sol-gel procedure. The all kinds of factors that effect the morphology of monolith column were investigated. The results showed that the structure of monolithic column could be adjusted easily through altering the composition of sol solution.
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25
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Wu M, Wu R, Zhang Z, Zou H. Preparation and application of organic-silica hybrid monolithic capillary columns. Electrophoresis 2010; 32:105-15. [DOI: 10.1002/elps.201000349] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 09/21/2010] [Accepted: 09/21/2010] [Indexed: 11/08/2022]
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26
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Wu M, Chen Y, Wu R, Li R, Zou H, Chen B, Yao S. The synthesis of chloropropyl-functionalized silica hybrid monolithic column with modification of N,N-dimethyl-N-dodecylamine for capillary electrochromatography separation. J Chromatogr A 2010; 1217:4389-94. [DOI: 10.1016/j.chroma.2010.03.019] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 03/06/2010] [Accepted: 03/12/2010] [Indexed: 10/19/2022]
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27
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Zaidi SA, Han KM, Hwang DG, Cheong WJ. Preparation of open tubular molecule imprinted polymer capillary columns with various templates by a generalized procedure and their chiral and non-chiral separation performance in CEC. Electrophoresis 2010; 31:1019-28. [DOI: 10.1002/elps.200900457] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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28
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Nischang I, Tallarek U. Inherent peak compression of charged analytes in electrochromatography. J Sep Sci 2010; 32:3157-68. [PMID: 19746396 DOI: 10.1002/jssc.200900436] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This work resolves peak compression of charged analytes in CEC with strong cation-exchange stationary phase particles. By combining electrochromatographic peak shape analysis with the results of numerical simulations and confocal laser scanning microscopy in the packed capillaries, we identify electrical field-induced concentration polarization as the key physical phenomenon responsible for the inherent existence of local electrical field gradients on the scale of an individual support particle. Consequently, positive and negative field gradients exist between and inside the particles along the whole packing. Their intensity depends on the particles cation-selectivity (governed by the particles volume charge density and the mobile phase ionic strength) and the applied field strength. The interplay of these local field gradients with the analytes retention (intraparticle adsorption) determines whether fronting, tailing, or spiked analyte peaks are observed, and it provides a mechanism by which strongly retained analytes can be eluted over long distances with little zone dispersion. Our analysis explains the "anomalous" peak compression effects with strong cation-exchange particles, which have been reported more than a decade ago (Smith, N. W., Evans, M. B., Chromatographia 1995, 41, 197-203) and since then remained largely unresolved.
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Affiliation(s)
- Ivo Nischang
- Department of Chemistry, Philipps-Universität Marburg, Marburg, Germany
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Velamakanni A, Blackwell DL, Yang D, Sonawane S, Addagulla S, Major JS. Synthesis and characterization of functionalized silane-based copolymers for thermally robust polymer–silica hybrids. Polym Chem 2010. [DOI: 10.1039/c0py00042f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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30
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Ye F, Wang S, Zhao S. Preparation and characterization of mixed-mode monolithic silica column for capillary electrochromatography. J Chromatogr A 2009; 1216:8845-50. [DOI: 10.1016/j.chroma.2009.10.071] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 10/16/2009] [Accepted: 10/23/2009] [Indexed: 11/27/2022]
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31
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Li T, Xu Y, Feng YQ. Open Tubular Capillary Electrochromatographic Separation of Proteins and Peptides Using a TiO2 Nanoparticle-Deposited Capillary by Liquid Phase Deposition. J LIQ CHROMATOGR R T 2009. [DOI: 10.1080/10826070903248411] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Ting Li
- a Department of Chemistry , Wuhan University , Wuhan, P. R. China
| | - Ying Xu
- a Department of Chemistry , Wuhan University , Wuhan, P. R. China
| | - Yu-Qi Feng
- a Department of Chemistry , Wuhan University , Wuhan, P. R. China
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32
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Lu M, Feng Q, Lu Q, Cai Z, Zhang L, Chen G. Preparation and evaluation of the highly cross-linked poly(1-hexadecane-co-trimethylolpropane trimethacrylate) monolithic column for capillary electrochromatography. Electrophoresis 2009; 30:3540-7. [DOI: 10.1002/elps.200900018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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33
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Goubert-Renaudin S, Etienne M, Brandès S, Meyer M, Denat F, Lebeau B, Walcarius A. Factors affecting copper(II) binding to multiarmed cyclam-grafted mesoporous silica in aqueous solution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:9804-9813. [PMID: 19591478 DOI: 10.1021/la900892q] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Single- as well as multi-anchored cyclam-functionalized silica samples have been prepared by grafting amorphous silica gel (K60) and mesostructured silica (SBA-15) with silylated cyclam precursors bearing one, two, or four triethoxysilyl groups, respectively ascribed to cyclam-mono, cyclam-di, and cyclam-tetra. Their reactivity toward copper(II) has been thoroughly investigated in aqueous solution and discussed with respect to the number of arms tethering the ligand to the silica surface and the structural ordering of the adsorbent in terms of capacity, long-term stability, and speed of access to the binding sites. Less-than-complete metal ion uptake was always observed, even in excess of cyclam groups with respect to solution-phase Cu(II), suggesting lower stability of immobilized complexes relative to those in solution. Therefore, the number of arms attaching cyclam moieties to the silica walls (one, two, or four) was found to dramatically affect the binding properties of these hybrids toward copper(II), revealing significantly larger capacities when reducing the number of arms (less rigidity constraints in the macrocycle). In parallel, multiarm tethering resulted in better chemical resistance toward degradation as evidenced by UV-visible monitoring of Cu-cyclam complexes in solution (i.e., more ligand leaching from the adsorbent for singly tethered cyclam). On the other hand, electron spin resonance (ESR) experiments did not evidence significant differences between complexes bearing one, two, or four alkyl arms, since all Cu(II)-cyclam surface complexes were found to be hexacoordinated with a strong equatorial ligand field. Comparison of amorphous gels and mesostructured materials indicates that the binding properties of the adsorbents were hardly influenced by their level of ordering, suggesting that accessibility to the binding sites was not the limiting factor. Some advantage belonging to mesostructured adsorbents was however observed with respect to the rate of access to the active centers at pH values close to neutrality (due to faster mass transport), but this was no more the case when operating at lower pH values where the formation of the Cu-cyclam complex became the rate-determining step, as pointed out by electrochemistry.
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Affiliation(s)
- Stéphanie Goubert-Renaudin
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, UMR 7564, CNRS - Nancy-Universite, 405 rue de Vandoeuvre, 54600 Villers-les-Nancy, France
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34
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Capillary microextraction (CME) and its application to trace elements analysis and their speciation. Anal Chim Acta 2009; 650:23-32. [DOI: 10.1016/j.aca.2009.04.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 04/02/2009] [Accepted: 04/02/2009] [Indexed: 11/18/2022]
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35
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36
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Messina A, Moroni S, Flieger M, Sinibaldi M, Ursini O. CEC enantioseparations of carboxylic acids on silica-based monoliths modified with ergot alkaloid derivative. Electrophoresis 2009; 30:2890-6. [DOI: 10.1002/elps.200800788] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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37
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Lin X, Zeng W, Wang X, Xie Z. Glycin-bonded silica monolithic column as zwitterionic stationary phase for hydrophilic interaction pressurized capillary electrochromatography. J Sep Sci 2009; 32:2767-75. [DOI: 10.1002/jssc.200900107] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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38
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Szumski M, Buszewski B. Effect of temperature during photopolymerization of capillary monolithic columns. J Sep Sci 2009; 32:2574-81. [DOI: 10.1002/jssc.200900220] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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39
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Wu M, Wu R, Wang F, Ren L, Dong J, Liu Z, Zou H. "One-pot" process for fabrication of organic-silica hybrid monolithic capillary columns using organic monomer and alkoxysilane. Anal Chem 2009; 81:3529-36. [PMID: 19402722 DOI: 10.1021/ac9000749] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A "one-pot" process for the preparation of organic-silica hybrid capillary monolithic columns by concurrently using organic monomers and alkoxysilanes was described. In this process, the hydrolyzed alkoxysilanes of tetramethoxysilane (TMOS) and vinyltrimethoxysilane (VTMS) as precursors for the synthesis of a silica-based monolith using the sol-gel method and the organic monomer (allyldimethyldodecylammonium bromide (ADDAB) or acrylamide (AA)) with vinyl groups for free radical polymerization along with the initiator of azobisisobutyronitrile (AIBN) were concurrently introduced into a pretreated capillary; after that, the polycondensation of alkoxysilanes and the copolymerization of organic monomers and as-precondensed siloxanes were subsequently carried out within the confines of a capillary at the proper reaction conditions. Two types of organic-silica hybrid capillary monolithic columns with hydrophobic and hydrophilic properties have been fabricated, respectively, by this "one-pot" process using two different organic monomers of ADDAB and AA. The morphologies of the synthesized organic-silica hybrid monolithic columns were characterized by scanning electron microscopy (SEM). The performances of these organic-silica monolithic columns were investigated by capillary electrochromatography (CEC). The retention behaviors of the neutral and polar compounds on the resulting hydrophobic and hydrophilic organic-silica hybrid monolithic columns confirmed the successful incorporation of organic monomers in the silica monolithic matrix. In addition, the ADDA-silica hybrid capillary monolithic column was also applied in the analysis of tryptic digests of bovine serum albumin (BSA) and mouse liver extract by microliquid chromatography-tandem mass spectrometry (microLC-MS/MS) for demonstrating its potential in proteome analysis.
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Affiliation(s)
- Minghuo Wu
- Key Laboratory of Separation Science for Analytical Chemistry, National Chromatographic R & A Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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40
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Improvement of chromatographic performances of in-situ synthesized hybrid C8 silica monoliths by reduction of structural radial heterogeneities. J Chromatogr A 2009; 1216:3857-63. [DOI: 10.1016/j.chroma.2009.02.070] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 02/19/2009] [Accepted: 02/23/2009] [Indexed: 11/20/2022]
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41
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Etienne M, Goubert-Renaudin S, Rousselin Y, Marichal C, Denat F, Lebeau B, Walcarius A. Multiarm cyclam-grafted mesoporous silica: a strategy to improve the chemical stability of silica materials functionalized with amine ligands. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:3137-3145. [PMID: 19437717 DOI: 10.1021/la8032379] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We have explored in this work the stability and the reactivity of multiarm cyclam-grafted mesoporous silica samples in aqueous solution. A series of hybrid materials have been prepared by grafting silylated cyclam molecules bearing one, two, or four silyl groups onto both amorphous silica gel (K60) and ordered mesoporous silica (SBA15). Under these conditions, cyclam moieties are attached to the silica walls via one, two, or four arms. Various physicochemical techniques have been applied to characterize the functionalized solids (elemental analysis, 1H-29Si and 1H-13C CPMAS NMR, and N2 adsorption-desorption isotherms). The interest in two and four arms for improving the chemical stability in solution, by comparison with the system displaying only one arm, has been demonstrated by using a set of complementary experiments involving pH measurements and silicon determination with ICP-AES. Then, the investigation of their protonation and binding properties toward copper(II) has revealed a significant decrease in the reactivity of these hybrids as a consequence of multiarm tethering. A comparison of amorphous and ordered materials has permitted us to point out the influence of mesostructuration on the reactivity of these functionalized solids, especially from a kinetic point of view.
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Affiliation(s)
- Mathieu Etienne
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, UMR 7564, CNRS-Nancy-University, 405, rue de Vandoeuvre, F-54600 Villers-les-Nancy, France.
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42
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Walcarius A, Collinson MM. Analytical chemistry with silica sol-gels: traditional routes to new materials for chemical analysis. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2009; 2:121-143. [PMID: 20636056 DOI: 10.1146/annurev-anchem-060908-155139] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The versatility of sol-gel chemistry enables us to generate a wide range of silica and organosilica materials with controlled structure, composition, morphology and porosity. These materials' hosting and recognition properties, as well as their wide-open structures containing many easily accessible active sites, make them particularly attractive for analytical purposes. In this review, we summarize the importance of silica sol-gels in analytical chemistry by providing examples from the separation sciences, optical and electrochemical sensors, molecular imprinting, and biosensors. Recent work suggests that manipulating the structure and composition of these materials at different scales (from molecular to macromolecular states and/or from micro- to meso- and/or macroporous levels) promises to generate chemical and biochemical sensing devices with improved selectivity and sensitivity.
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Affiliation(s)
- Alain Walcarius
- Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, CNRS-Nancy Université, F-54600 Villers-les-Nancy, France.
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43
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Randon J, Guerrin JF, Rocca JL. Synthesis of titania monoliths for chromatographic separations. J Chromatogr A 2008; 1214:183-6. [DOI: 10.1016/j.chroma.2008.10.108] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Revised: 10/14/2008] [Accepted: 10/23/2008] [Indexed: 11/30/2022]
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44
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45
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Fan LQ, Zhang YP, Ye XW, Zhang YJ, Li B, Lee KP. Rapid Preparation of Monolithic Silica Column for Electrophoretic and Chromatographic Separation by Microwave Irradiation. J LIQ CHROMATOGR R T 2008. [DOI: 10.1080/10826070802548606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Li Qun Fan
- a Henan Institute of Science and Technology , Xinxiang, P. R. China
| | - Yu Ping Zhang
- a Henan Institute of Science and Technology , Xinxiang, P. R. China
| | - Xiong Wen Ye
- a Henan Institute of Science and Technology , Xinxiang, P. R. China
| | - Yi Jun Zhang
- a Henan Institute of Science and Technology , Xinxiang, P. R. China
| | - Bo Li
- a Henan Institute of Science and Technology , Xinxiang, P. R. China
| | - Kwang Pill Lee
- b Department of Chemistry , Graduate School, Kyungpook National University , South Korea
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Ye F, Collinson MM, Higgins DA. What can be learned from single molecule spectroscopy? Applications to sol-gel-derived silica materials. Phys Chem Chem Phys 2008; 11:66-82. [PMID: 19081909 DOI: 10.1039/b812924j] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Single molecule spectroscopic methods are now being widely employed to probe the nanometer scale properties of sol-gel-derived silica materials. This article reviews a subset of the recent literature in this area and provides salient examples of the new information that can be obtained. The materials covered include inorganic and organically-modified silica, along with surfactant-templated mesoporous materials. Studies of molecule-matrix interactions based on ionic, hydrogen bonding and hydrophobic interactions are reviewed, highlighting the impacts of these interactions on mass transport phenomena. Quantitative investigations of molecular diffusion by single molecule tracking and fluorescence correlation spectroscopy are also covered, focusing on the characterization of anisotropic and hindered diffusion in mesoporous systems. Single molecule polarity studies are described and the new information that can be obtained from the resulting inhomogeneous distributions is discussed. Likewise, single molecule studies of silica acidity properties are reviewed, including observation of nanoscale buffering phenomena due to the chemistry of surface silanols. Finally, related single nanoparticle studies of macroporous silicas are also discussed.
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Affiliation(s)
- Fangmao Ye
- Department of Chemistry, Kansas State University, KS, 66506, Manhattan, USA
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47
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Li H, Liu X, Niu W, Zhu S, Fan L, Shi L, Xu G. CEC with tris(2,2′-bipyridyl) ruthenium(II) electrochemiluminescent detection. Electrophoresis 2008; 29:4475-81. [DOI: 10.1002/elps.200800088] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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48
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Shi ZG, Wei F, Feng YQ. A Novel Approach to Prepare a Glass-Fiber-Packed Capillary Column for Capillary Electrochromatography. J LIQ CHROMATOGR R T 2008. [DOI: 10.1080/10826070802480008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Zhi-Guo Shi
- a Department of Chemistry, Wuhan University , Wuhan, P. R. China
| | - Fang Wei
- a Department of Chemistry, Wuhan University , Wuhan, P. R. China
| | - Yu-Qi Feng
- a Department of Chemistry, Wuhan University , Wuhan, P. R. China
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49
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Ding GS, Tang AN. Capillary electrochromatographic separation of racemates on a norvancomycin-bonded monolithic column under reversed-phase conditions. J Chromatogr A 2008; 1208:232-8. [DOI: 10.1016/j.chroma.2008.08.075] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 08/21/2008] [Accepted: 08/21/2008] [Indexed: 11/30/2022]
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50
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Jezorek JR, Gu RF, Dean TH, Sabus CL, Sha X. Simultaneous Separation of Inorganic Ions and Neutral Organics on a Sol-Gel-Coated Capillary using Combined Capillary Zone Electrophoresis and Capillary Electrochromatography. J LIQ CHROMATOGR R T 2008. [DOI: 10.1080/10826070802424535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- John R. Jezorek
- a Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro, North Carolina, USA
| | - Rong-Fang Gu
- a Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro, North Carolina, USA
| | - Tricia H. Dean
- a Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro, North Carolina, USA
| | - Chantel L. Sabus
- a Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro, North Carolina, USA
| | - Xin Sha
- a Department of Chemistry and Biochemistry , The University of North Carolina at Greensboro , Greensboro, North Carolina, USA
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