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Wang J, Si J, Li J, Zhang P, Wang Y, Zhang W, Jin B, Li W, Li N, Miao S. Self-Propelled Nanojets for Fenton Catalysts Based on Halloysite with Embedded Pt and Outside-Grafted Fe 3O 4. ACS APPLIED MATERIALS & INTERFACES 2021; 13:49017-49026. [PMID: 34614350 DOI: 10.1021/acsami.1c13974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Taking inspirations from nature, we endeavor to develop catalytically self-propelled nanojets from a type of tubular clay minerals, halloysite nanotubes (HNTs), and utilize them as catalysts targeted for catalysis where the traditional means of mechanical agitation cannot be implemented. Nanojets of Fe3O4@HNTs/Pt were prepared by impregnating platinum nanoparticles (Pt NPs) in lumens of HNTs and selective grafting of magnetite (Fe3O4) particles on the external surface. The HNT-based nanojets were validated to be highly suitable both in free bulk solution and in microfluidic flow. An example of Fenton degradation catalyzed by these jets was demonstrated. The powerful movement of Fe3O4@HNTs/Pt (368 ± 50 μm·s-1) fueled by 5.0% wt. H2O2 was found to follow a bubble propulsion mechanism, and the motion exhibits collective behavior as swarms. The clay tubes were for the first time observed to self-assemble into fish-like aggregates during swimming, reflecting natural occurrence of motion-evolution philosophy. Guided motion was realized by employing magnetic manipulation which makes jets feasible for reactors with complex microchannels/reactors.
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Affiliation(s)
- Jian Wang
- Key Laboratory of Automobile Materials of Ministry of Education, School of Materials Science and Engineering, Solid Waste Recycling Engineering Research Center of Jilin Province, Open Research Laboratory for Physicochemical Testing Methods of Functional Minerals-Ministry of Natural Resources, Jilin University, Changchun 130022, China
| | - Jiwen Si
- Key Laboratory of Automobile Materials of Ministry of Education, School of Materials Science and Engineering, Solid Waste Recycling Engineering Research Center of Jilin Province, Open Research Laboratory for Physicochemical Testing Methods of Functional Minerals-Ministry of Natural Resources, Jilin University, Changchun 130022, China
| | - Jingyao Li
- Key Laboratory of Automobile Materials of Ministry of Education, School of Materials Science and Engineering, Solid Waste Recycling Engineering Research Center of Jilin Province, Open Research Laboratory for Physicochemical Testing Methods of Functional Minerals-Ministry of Natural Resources, Jilin University, Changchun 130022, China
| | - Peiping Zhang
- Key Laboratory of Automobile Materials of Ministry of Education, School of Materials Science and Engineering, Solid Waste Recycling Engineering Research Center of Jilin Province, Open Research Laboratory for Physicochemical Testing Methods of Functional Minerals-Ministry of Natural Resources, Jilin University, Changchun 130022, China
| | - Yan Wang
- School of Materials Science & Engineering, and Electron Microscopy Center, Jilin University, Changchun 130012, China
| | - Wei Zhang
- School of Materials Science & Engineering, and Electron Microscopy Center, Jilin University, Changchun 130012, China
| | - Bo Jin
- Key Laboratory of Automobile Materials of Ministry of Education, School of Materials Science and Engineering, Solid Waste Recycling Engineering Research Center of Jilin Province, Open Research Laboratory for Physicochemical Testing Methods of Functional Minerals-Ministry of Natural Resources, Jilin University, Changchun 130022, China
| | - Wenqing Li
- Key Laboratory of Mineral Resources Evaluation in Northeast Asia, Ministry of Natural Resources, Changchun 130061, China
| | - Nan Li
- Key Laboratory of Automobile Materials of Ministry of Education, School of Materials Science and Engineering, Solid Waste Recycling Engineering Research Center of Jilin Province, Open Research Laboratory for Physicochemical Testing Methods of Functional Minerals-Ministry of Natural Resources, Jilin University, Changchun 130022, China
| | - Shiding Miao
- Key Laboratory of Automobile Materials of Ministry of Education, School of Materials Science and Engineering, Solid Waste Recycling Engineering Research Center of Jilin Province, Open Research Laboratory for Physicochemical Testing Methods of Functional Minerals-Ministry of Natural Resources, Jilin University, Changchun 130022, China
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Rajeswari A, Ramdass A, Muthu Mareeswaran P, Velayudham M, Rajagopal S. Electron transfer reactions of osmium(II) complexes with phenols and phenolic acids. J Mol Struct 2016. [DOI: 10.1016/j.molstruc.2016.02.088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lee HK, Lee SG, Jeon DH. Numerical Studies of Flow Characteristics and Particle Residence Time in a Taylor Reactor. APPLIED CHEMISTRY FOR ENGINEERING 2015. [DOI: 10.14478/ace.2014.1117] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Jaquins-Gerstl A, Shu Z, Zhang J, Liu Y, Weber SG, Michael AC. Effect of dexamethasone on gliosis, ischemia, and dopamine extraction during microdialysis sampling in brain tissue. Anal Chem 2011; 83:7662-7. [PMID: 21859125 PMCID: PMC3193568 DOI: 10.1021/ac200782h] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microdialysis sampling of the brain is an analytical technique with numerous applications in neuroscience and the neurointensive care of brain-injured human patients. Even so, implanting microdialysis probes into brain tissue causes a penetration injury that triggers gliosis (the activation and proliferation of glial cells) and ischemia (the interruption of blood flow). Thus, the probe samples injured tissue. Mitigating the effects of the penetration injury might refine the technique. The synthetic glucocorticoid dexamethasone is a potent anti-inflammatory and immunosuppressant substance. We performed microdialysis in the rat brain for 5 days, with and without dexamethasone in the perfusion fluid (10 μM for the first 24 h and 2 μM thereafter). On the first and fourth day of the perfusion, we performed dopamine no-net-flux measurements. On the fifth day, we sectioned and stained the brain tissue and examined it by fluorescence microscopy. Although dexamethasone profoundly inhibited gliosis and ischemia around the probe tracks it had only modest effects on dopamine no-net-flux results. These findings show that dexamethasone is highly effective at suppressing gliosis and ischemia but is limited in its neuroprotective activity.
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Affiliation(s)
- Andrea Jaquins-Gerstl
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Zhan Shu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Jing Zhang
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Yansheng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Stephen G. Weber
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Adrian C. Michael
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
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Xu H, Weber SG. Effect of an open tube in series with a packed capillary column on liquid chromatographic performance. The influence of particle diameter, temperature, and system pressure. J Chromatogr A 2009; 1216:1346-52. [PMID: 19150071 PMCID: PMC2663968 DOI: 10.1016/j.chroma.2008.12.060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Revised: 12/16/2008] [Accepted: 12/22/2008] [Indexed: 10/21/2022]
Abstract
A postcolumn reactor or a simple open tube connecting a capillary column to, for example, a mass spectrometer affects the performance of a capillary liquid chromatography system in two ways: stealing pressure from the column and adding band-spreading. This effect is especially intolerable in fast separations. Our calculations show that in the presence of a 25 microm radius postcolumn reactor, column (50 microm radius) efficiency (number of theoretical plates) is severely reduced by more than 75% with a t(0) of 10s and a particle diameter from 1 to 5 microm for unretained solutes at room temperature. Therefore, it is necessary to minimize the reactor's effect and to improve the column efficiency by optimizing postcolumn conditions. We derived an equation that defines the observed number of theoretical plates (N(obs)) taking into account the two effects stated above, which is a function of the maximum pressure P(m), the particle diameter d(p), the reactor radius a(r), the column radius a(c), the desired dead time t(0), the column temperature T and zone capacity factor k''. Poppe plots were obtained by calculations using this equation. The results show that for a t(0) shorter than 18s, a P(m) of 4000 psi, and a d(p) of 1.7 microm, a 5 microm radius reactor has to be used. Such a small reactor is difficult to fabricate. Fortunately, high temperature helps to minimize the reactor effect so that reactors with manageable radius (larger than 12.5 microm) can be used in many practical conditions. Furthermore, solute retention diminishes the influence of a postcolumn reactor. Thus, a 12.5 microm reactor supersedes a 5 microm reactor for retained solutes even at a t(0) of 5s (k''>3.8, or k'>2.0).
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Affiliation(s)
- Hongjuan Xu
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA 15260, USA
| | - Stephen G. Weber
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA 15260, USA
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Xu H, Weber SG. Optimization of post-column reactor radius in capillary high performance liquid chromatography Effect of chromatographic column diameter and particle diameter. J Chromatogr A 2006; 1113:116-22. [PMID: 16494886 PMCID: PMC1839062 DOI: 10.1016/j.chroma.2006.01.129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2005] [Revised: 01/26/2006] [Accepted: 01/30/2006] [Indexed: 11/20/2022]
Abstract
A post-column reactor consisting of a simple open tube (Capillary Taylor Reactor) affects the performance of a capillary LC in two ways: stealing pressure from the column and adding band spreading. The former is a problem for very small radius reactors, while the latter shows itself for large reactor diameters. We derived an equation that defines the observed number of theoretical plates (N(obs)) taking into account the two effects stated above. Making some assumptions and asserting certain conditions led to a final equation with a limited number of variables, namely chromatographic column radius, reactor radius and chromatographic particle diameter. The assumptions and conditions are that the van Deemter equation applies, the mass transfer limitation is for intraparticle diffusion in spherical particles, the velocity is at the optimum, the analyte's retention factor, k', is zero, the post-column reactor is only long enough to allow complete mixing of reagents and analytes and the maximum operating pressure of the pumping system is used. Optimal ranges of the reactor radius (a(r)) are obtained by comparing the number of observed theoretical plates (and theoretical plates per time) with and without a reactor. Results show that the acceptable reactor radii depend on column diameter, particle diameter, and maximum available pressure. Optimal ranges of a(r) become narrower as column diameter increases, particle diameter decreases or the maximum pressure is decreased. When the available pressure is 4000 psi, a Capillary Taylor Reactor with 12 microm radius is suitable for all columns smaller than 150 microm (radius) packed with 2-5 microm particles. For 1 microm packing particles, only columns smaller than 42.5 microm (radius) can be used and the reactor radius needs to be 5 microm.
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Affiliation(s)
- Hongjuan Xu
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA 15260, USA
| | - Stephen G. Weber
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA 15260, USA
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Jung MC, Shi G, Borland L, Michael AC, Weber SG. Simultaneous determination of biogenic monoamines in rat brain dialysates using capillary high-performance liquid chromatography with photoluminescence following electron transfer. Anal Chem 2006; 78:1755-60. [PMID: 16536408 PMCID: PMC1488825 DOI: 10.1021/ac051183g] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Simultaneous determination of biogenic monoamines such as dopamine, serotonin, and 3-methoxytyramine in brain is important in understanding neurotransmitter activity. This study presents a sensitive determination of biogenic monoamines in rat brain striatum microdialysates using capillary high-performance liquid chromatography with the photoluminescence following electron-transfer detection technique. Separation conditions were optimized by changing the concentration of an ion-interaction agent and the percentage of an organic modifier. The high concentration of ion-interaction agent enabled the amines as a class to be separated from interfering acids, but also made the separation very long. To shorten the separation time, 10% (v/v) acetonitrile was used as the organic modifier. Eight chromatographic runs during a 3-h period were analyzed in terms of retention times, peak heights, and peak widths. Chromatograms are very reproducible, with less than 1% changes in peak height over 3 h. Typical concentration detection limits at the optimum separation conditions were less than 100 pM for metabolic acids and approximately 200 pM for monoamines. The injection volume of the sample was 500 nL. Thus, the mass detection limits were less than 50 amol for metabolic acids and approximately 100 amol for monoamines. Typical separation time was less than 10 min. To validate the technique, the separation method was applied to the observation of drug-induced changes of monoamine concentrations in rat brain microdialysis samples. Local perfusion of tetrodotoxin, a sodium channel blocker, into the striatum of an anesthetized rat decreased dopamine, 3-methoxytyramine, and serotonin concentrations in dialysates. Successive monitoring of striatal dialysates at a temporal resolution of 7.7 min showed that the injection of nomifensine transiently increased dopamine and 3-methoxytyramine concentrations in rat brain dialysate.
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Affiliation(s)
- Moon Chul Jung
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Guoyue Shi
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Laura Borland
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Adrian C. Michael
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Stephen G. Weber
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
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Jung MC, Munro N, Shi G, Michael AC, Weber SG. Use of tris(2,2'-bipyridine)osmium as a photoluminescence-following electron-transfer reagent for postcolumn detection in capillary high-performance liquid chromatography. Anal Chem 2006; 78:1761-8. [PMID: 16536409 PMCID: PMC1482471 DOI: 10.1021/ac051182o] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photoluminescence-following electron-transfer (PFET) technique, developed in our laboratory, is a sensitive chromatographic detection method for oxidizable analytes. Because the oxidations are homogeneous, the technique avoids the problem of electrode fouling. A liquid-phase oxidant reacts with the electrochemically active analytes after separation, becoming capable of photoluminescence. Laser-induced photoluminescence is measured to quantitate the analytes. Thus, the electrochemical properties of the oxidant determine the detection selectivity, and the spectroscopic properties define the sensitivity. The properties of tris(2,2'-bipyridine)osmium (1) were investigated for use as the liquid-phase oxidant in the PFET system. The redox potential of the complex is less positive than that of tris(2,2'-bipyridine)ruthenium (2); thus, on-line generation of 1(3+) by reaction with PbO2, and selective oxidation of catechols by 1(3+), was possible. The mild oxidizing power of 1(3+) led to a lower background signal (compared to 2(3+)) when mixed with acidic mobile phases. Photoluminescence from 1(2+) was much weaker than that from 2(2+); nonetheless, the system achieved subnanomolar detection limits for dopamine, 3-methoxytyramine, and serotonin. Dopamine and 3-methoxytyramine in rat brain striatal dialysates were determined before and after the injection of nomifensine. The pH of the mobile phase can govern the detection selectivity, since oxidation of most organics is accompanied by proton transfer. Reaction of 1 with catechols showed pH-dependent sensitivity resulting from pH-dependent reaction rate changes. Since the reaction rate is also temperature dependent, increased temperature at the mixer resulted in higher sensitivity. However, the noise level also increased at elevated temperature; thus, the detection limit did not improve.
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Affiliation(s)
- Moon Chul Jung
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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