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Gromotka L, Uttinger MJ, Schlumberger C, Thommes M, Peukert W. Classification and characterization of multimodal nanoparticle size distributions by size-exclusion chromatography. NANOSCALE 2022; 14:17354-17364. [PMID: 36378146 DOI: 10.1039/d2nr04688a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Size-exclusion chromatography (SEC) is a well-known, versatile and scalable technique for the separation of molecules according to their hydrodynamic size in solution as well as for the determination of molecular weight distributions of polymers. In this paper we demonstrate and generalize the applicability of SEC to the classification and characterization of multimodal distributions of nanoparticles over a broad size range. After calibration with gold standards from 5 nm to 80 nm, the calibration curve is used to determine the particle size distributions (PSDs) of the standards which are in agreement with comprehensive nanoparticle size analysis by analytical ultracentrifugation. Universal calibration curves independent of the core material and surface functionality can be constructed if the pore diameter of the stationary phase exceeds the particle diameter by a factor of 2-3. Mixtures of gold standards are separated by SEC and evaluated in terms of peak resolution and size-dependent separation curves depending on how well the individual peaks are resolved. Baseline separation of a multimodal mixture is observed and its PSD is determined. Mixtures can be fractionated into coarse and fine fractions with nm precision at different switching times of the fraction collector. Our study demonstrates the strength of SEC to classify multimodal PSDs as well as to accurately determine size distributions of complex nanoparticle dispersions over a broad size range.
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Affiliation(s)
- Lukas Gromotka
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen, -Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany.
| | - Maximilian Johannes Uttinger
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen, -Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany.
| | - Carola Schlumberger
- Institute of Separation Science and Technology (TVT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 3, 91058 Erlangen, Germany
| | - Matthias Thommes
- Institute of Separation Science and Technology (TVT), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Egerlandstraße 3, 91058 Erlangen, Germany
| | - Wolfgang Peukert
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen, -Nürnberg (FAU), Cauerstraße 4, 91058 Erlangen, Germany.
- Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany
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Annušová A, Bodík M, Hagara J, Kotlár M, Halahovets Y, Mičušík M, Chlpík J, Cirák J, Hofbauerová M, Jergel M, Majková E, Šiffalovič P. On the extraction of MoO x photothermally active nanoparticles by gel filtration from a byproduct of few-layer MoS 2 exfoliation. NANOTECHNOLOGY 2020; 32:045708. [PMID: 33140739 DOI: 10.1088/1361-6528/abc035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Gel filtration is a versatile technique employed for biological molecules and nanoparticles, offering their reproducible classification based on size and shape. Colloidal nanoparticles are of significant interest in biomedical applications due to a large number of solution-based bioconjugation procedures. Nevertheless, the inherent polydispersity of the nanoparticles produced by various techniques necessitates the employment of high yield separation and purification techniques. Here we demonstrate the employment of gel filtration on non-stoichiometric plasmonic MoO x nanoparticles, prepared by an oxidation process during liquid-phase exfoliation of few-layer MoS2 nanosheets. This resulted in the separation of two types of MoO x particles, in the form of two different chromatographic fractions. They showed different sizes, morphological and optical properties. The fraction containing smaller particles with diameters of 1-4 nm, exhibited an increased absorbance peak in the near IR region and responded with a significant temperature increase to laser irradiation at the wavelength close to the maximal absorption. The fraction with the larger particles from 3 up to 10 nm, showed weak photoluminescence and a preferred orientation upon the deposition on a planar substrate. However, it had no absorbance in the near IR compared to the former fraction. According to our knowledge, this is the first time that the gel filtration was applied to the separation of molybdenum oxide nanomaterials. This step ensured the isolation of plasmonic MoO x nanoparticles suitable for further bioconjugation and target photothermal treatment.
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Affiliation(s)
- Adriana Annušová
- Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava, Slovakia. Centre for Advanced Material Application, Slovak Academy of Sciences, Dúbravská cesta 9, 845 11 Bratislava, Slovakia
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Süβ S, Bartsch K, Wasmus C, Damm C, Segets D, Peukert W. Chromatographic property classification of narrowly distributed ZnS quantum dots. NANOSCALE 2020; 12:12114-12125. [PMID: 32484198 DOI: 10.1039/d0nr03890c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Although optimized synthesis methods for nanoparticles (NPs) on small scale can lead to narrow particle size distributions (PSDs) and thus defined optical properties, in particular during scale-up, an additional classification step must be applied to adjust the particle properties according to the needs of the later application. NP chromatography is a promising separation method, which can be potentially transferred to preparative and industrial scale. Herein, we demonstrate that remarkable classification of ZnS quantum dots (QDs) with respect to the fundamental band gap energy is achieved by chromatography although the PSD of the feed material is already very narrow (1.5-3.0 nm). We investigated the interactions of ZnS QDs with stationary and mobile phase materials in order to select a proper material couple so that irreversible NP adhesion, agglomeration, decomposition or dissolution of the ZnS QDs during the chromatographic experiments are avoided and highly reproducible chromatograms are obtained. Using a fraction collector, the already narrowly size distributed feed material was separated into coarse and fine fractions with distinct band gap energies. For characterization of the chromatographic fractionation, quantities known from particle technology, i.e. separation efficiency, cut size and yield, were adapted to the band gap energy distributions accessible from UV/Vis spectroscopy. The optimization of process conditions (flow rate, temperature, switching time of the fraction collector) allows fine-tuning of the property classification and therefore of the optical properties within the narrow distribution of the ZnS QDs. Our study shows the strength and high potential of chromatography for preparative and continuous separation of NPs even in case of narrow size-distributed sub-10 nm semiconductor QDs.
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Affiliation(s)
- Sebastian Süβ
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058 Erlangen, Germany. and Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany
| | - Katja Bartsch
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058 Erlangen, Germany.
| | - Christina Wasmus
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058 Erlangen, Germany.
| | - Cornelia Damm
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058 Erlangen, Germany. and Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany
| | - Doris Segets
- Process Technology for Electrochemical Functional Materials, and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen (UDE), Carl-Benz-Straße 199, 47057 Duisburg, Germany
| | - Wolfgang Peukert
- Institute of Particle Technology (LFG), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 4, 91058 Erlangen, Germany. and Interdisciplinary Center for Functional Particle Systems (FPS), Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Haberstraße 9a, 91058 Erlangen, Germany
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Wu M, Mao Z, Chen K, Bachman H, Chen Y, Rufo J, Ren L, Li P, Wang L, Huang TJ. Acoustic Separation of Nanoparticles in Continuous Flow. ADVANCED FUNCTIONAL MATERIALS 2017; 27:1606039. [PMID: 29104525 PMCID: PMC5668689 DOI: 10.1002/adfm.201606039] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The separation of nanoscale particles based on their differences in size is an essential technique to the nanoscience and nanotechnology community. Here, nanoparticles are successfully separated in a continuous flow by using tilted-angle standing surface acoustic waves. The acoustic field deflects nanoparticles based on volume, and the fractionation of nanoparticles is optimized by tuning the cutoff parameters. The continuous separation of nanoparticlesis demonstrated with a ≈90% recovery rate. The acoustic nanoparticle separation method is versatile, non-invasive, and simple.
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Affiliation(s)
- Mengxi Wu
- Department of Engineering Science and Mechanics, The Pennsylvania State University, State College, PA 16802, USA
| | - Zhangming Mao
- Department of Engineering Science and Mechanics, The Pennsylvania State University, State College, PA 16802, USA
| | - Kejie Chen
- Department of Engineering Science and Mechanics, The Pennsylvania State University, State College, PA 16802, USA
| | - Hunter Bachman
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
| | - Yuchao Chen
- Department of Engineering Science and Mechanics, The Pennsylvania State University, State College, PA 16802, USA
| | - Joseph Rufo
- Department of Engineering Science and Mechanics, The Pennsylvania State University, State College, PA 16802, USA
| | - Liqiang Ren
- Department of Engineering Science and Mechanics, The Pennsylvania State University, State College, PA 16802, USA
| | - Peng Li
- Department of Engineering Science and Mechanics, The Pennsylvania State University, State College, PA 16802, USA
| | - Lin Wang
- Ascent Bio-Nano Technologies Inc., Research Triangle Park, NC 27709, USA
| | - Tony Jun Huang
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA
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Malysheva A, Lombi E, Voelcker NH. Bridging the divide between human and environmental nanotoxicology. NATURE NANOTECHNOLOGY 2015; 10:835-44. [PMID: 26440721 DOI: 10.1038/nnano.2015.224] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 08/28/2015] [Indexed: 05/17/2023]
Abstract
The need to assess the human and environmental risks of nanoscale materials has prompted the development of new metrological tools for their detection, quantification and characterization. Some of these methods have tremendous potential for use in various scenarios of nanotoxicology. However, in some cases, the limited dialogue between environmental scientists and human toxicologists has hampered the full exploitation of these resources. Here we review recent progress in the development of methods for nanomaterial analysis and discuss the use of these methods in environmental and human toxicology. We highlight the opportunities for collaboration between these two research areas.
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Affiliation(s)
- Anzhela Malysheva
- Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Enzo Lombi
- Centre for Environmental Risk Assessment and Remediation, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Nicolas H Voelcker
- ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Mawson Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
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Kato M, Sasaki M, Ueyama Y, Koga A, Sano A, Higashi T, Santa T. Comparison of the migration behavior of nanoparticles based on polyethylene glycol and silica using micellar electrokinetic chromatography. J Sep Sci 2015; 38:468-74. [DOI: 10.1002/jssc.201401086] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 11/12/2014] [Accepted: 11/12/2014] [Indexed: 01/14/2023]
Affiliation(s)
- Masaru Kato
- Graduate School of Pharmaceutical Sciences and GPLLI Program; The University of Tokyo; Tokyo Japan
| | - Minoru Sasaki
- Graduate School of Pharmaceutical Sciences and GPLLI Program; The University of Tokyo; Tokyo Japan
| | - Yukari Ueyama
- Faculty of Pharmaceutical Sciences; Tokyo University of Science; Noda-shi Chiba Japan
| | - Ayaka Koga
- Faculty of Pharmaceutical Sciences; Tokyo University of Science; Noda-shi Chiba Japan
| | - Akira Sano
- Faculty of Pharmaceutical Sciences; Tokyo University of Science; Noda-shi Chiba Japan
| | - Tatsuya Higashi
- Faculty of Pharmaceutical Sciences; Tokyo University of Science; Noda-shi Chiba Japan
| | - Tomofumi Santa
- Graduate School of Pharmaceutical Sciences and GPLLI Program; The University of Tokyo; Tokyo Japan
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López-Lorente ÁI, Valcárcel M. Separation Techniques of Gold Nanoparticles. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/b978-0-444-63285-2.00009-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2023]
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8
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Pharmacokinetics and Effects of Alkalization after Intravenous Administration of Eltenac in Horses. J Equine Vet Sci 2013. [DOI: 10.1016/j.jevs.2013.04.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Bokern S, Getze J, Agarwal S, Greiner A. Polymer grafted silver and copper nanoparticles with exceptional stability against aggregation by a high yield one-pot synthesis. POLYMER 2011. [DOI: 10.1016/j.polymer.2010.12.031] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Wu CS, Liu FK, Ko FH. Potential role of gold nanoparticles for improved analytical methods: an introduction to characterizations and applications. Anal Bioanal Chem 2010; 399:103-18. [DOI: 10.1007/s00216-010-4094-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 08/01/2010] [Accepted: 08/03/2010] [Indexed: 01/13/2023]
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Arita T, Yoshimura T, Adschiri T. Size exclusion chromatography of quantum dots by utilizing nanoparticle repelling surface of concentrated polymer brush. NANOSCALE 2010; 2:1467-1473. [PMID: 20820736 DOI: 10.1039/c0nr00157k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We have found that the concentrated poly(methyl methacrylate) (PMMA) brush showed the very good nanoparticles (NPs) repellency in its good solvent, e.g. tetrahydrofuran (THF). Whereas the oil- and hydro-phobic (fluorinated), hydrophobic and hydrophilic surfaces adsorbed a lot of NPs. The repellency of NPs did not depend on the surface nature of the NPs. Preparing absorption free columns for size exclusion chromatography (SEC) may enable us to separate quantum dots (QDs) and NPs according to their size. By installing the concentrated PMMA brush into silica monolith columns, we tried to achieve SEC of QDs and NPs. The concentrated PMMA brush immobilized silica monolith columns were prepared by surface initiated atom transfer polymerization of MMA. As a result, we have succeeded in separating QDs according to their size. This SEC system may be advantageous because it can be used in good solvents of the brush regardless of the stability of the surface modifier layer on the NPs.
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Affiliation(s)
- Toshihiko Arita
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aobaku, Sendai 980-8577, Japan.
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Liu FK, Chang YC. Using reversed-phase liquid chromatography to monitor the sizes of Au/Pt core/shell nanoparticles. J Chromatogr A 2010; 1217:1647-53. [DOI: 10.1016/j.chroma.2010.01.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 01/05/2010] [Accepted: 01/11/2010] [Indexed: 11/29/2022]
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Liu FK. Analysis and applications of nanoparticles in the separation sciences: A case of gold nanoparticles. J Chromatogr A 2009; 1216:9034-47. [DOI: 10.1016/j.chroma.2009.07.026] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 06/23/2009] [Accepted: 07/14/2009] [Indexed: 01/10/2023]
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17
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Liu FK. SEC Characterization of Au Nanoparticles Prepared through Seed-Assisted Synthesis. Chromatographia 2007. [DOI: 10.1365/s10337-007-0412-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Prakash C, Shaffer CL, Nedderman A. Analytical strategies for identifying drug metabolites. MASS SPECTROMETRY REVIEWS 2007; 26:340-69. [PMID: 17405144 DOI: 10.1002/mas.20128] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
With the dramatic increase in the number of new chemical entities (NCEs) arising from combinatorial chemistry and modern high-throughput bioassays, novel bioanalytical techniques are required for the rapid determination of the metabolic stability and metabolites of these NCEs. Knowledge of the metabolic site(s) of the NCEs in early drug discovery is essential for selecting compounds with favorable pharmacokinetic credentials and aiding medicinal chemists in modifying metabolic "soft spots". In development, elucidation of biotransformation pathways of a drug candidate by identifying its circulatory and excretory metabolites is vitally important to understand its physiological effects. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) have played an invaluable role in the structural characterization and quantification of drug metabolites. Indeed, liquid chromatography (LC) coupled with atmospheric pressure ionization (API) MS has now become the most powerful tool for the rapid detection, structure elucidation, and quantification of drug-derived material within various biological fluids. Often, however, MS alone is insufficient to identify the exact position of oxidation, to differentiate isomers, or to provide the precise structure of unusual and/or unstable metabolites. In addition, an excess of endogenous material in biological samples often suppress the ionization of drug-related material complicating metabolite identification by MS. In these cases, multiple analytical and wet chemistry techniques, such as LC-NMR, enzymatic hydrolysis, chemical derivatization, and hydrogen/deuterium-exchange (H/D-exchange) combined with MS are used to characterize the novel and isomeric metabolites of drug candidates. This review describes sample preparation and introduction strategies to minimize ion suppression by biological matrices for metabolite identification studies, the application of various LC-tandem MS (LC-MS/MS) techniques for the rapid quantification and identification of drug metabolites, and future trends in this field.
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Affiliation(s)
- Chandra Prakash
- Pfizer Global Research and Development, Eastern Point Road, Groton, Connecticut 06340, USA.
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Yamada K, Tokumoto Y, Nagata T, Mafuné F. Mechanism of Laser-induced Size-reduction of Gold Nanoparticles as Studied by Nanosecond Transient Absorption Spectroscopy. J Phys Chem B 2006; 110:11751-6. [PMID: 16800473 DOI: 10.1021/jp061020b] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Gold nanoparticles with an average diameter of approximately 8 nm (Au approximately 15,000) were irradiated with a tightly focused pulse laser at 355 nm in an aqueous solution of sodium dodecyl sulfate (SDS). Transient absorption spectra of the solution were measured at 25-100 ns after the laser irradiation. The observed transient absorption around 720 nm is assignable to the 2p <-- 1s transition of solvated electrons produced via multiple ionization of the gold nanoparticles. The nascent charge state of the gold nanoparticles was estimated from the transient absorbance. The dependence of the charge state on the SDS concentration shows a gradual increase from approximately +60 to approximately +70 in the 2 x 10(-4) to 3 x 10(-4) M range and an abrupt increase up to approximately +710 at the critical micelle concentration (CMC) of SDS, 8 x 10(-3) M. TEM measurements after laser irradiation reveal that the gold nanoparticles fragment into Au(approximately 1000) at a SDS concentration of 3 x 10(-4) M, whereas they are significantly dissociated into Au(approximately 100) above the CMC. The observed correlation between the nascent charge states and the extent of size reduction of the gold nanoparticles after the laser treatment indicates that the size reduction is caused by the Coulomb explosion of the highly charged gold nanoparticles. The mechanism of laser-induced size reduction is quantitatively discussed based on the liquid drop model.
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Affiliation(s)
- Kunihiro Yamada
- Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8902, Japan
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Current literature in mass spectrometry. JOURNAL OF MASS SPECTROMETRY : JMS 2005; 40:416-427. [PMID: 15751104 DOI: 10.1002/jms.804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of mass spectrometry. Each bibliography is divided into 11 sections: 1 Books, Reviews & Symposia; 2 Instrumental Techniques & Methods; 3 Gas Phase Ion Chemistry; 4 Biology/Biochemistry: Amino Acids, Peptides & Proteins; Carbohydrates; Lipids; Nucleic Acids; 5 Pharmacology/Toxicology; 6 Natural Products; 7 Analysis of Organic Compounds; 8 Analysis of Inorganics/Organometallics; 9 Surface Analysis; 10 Environmental Analysis; 11 Elemental Analysis. Within each section, articles are listed in alphabetical order with respect to author (4 Weeks journals - Search completed at 12th. Jan. 2005).
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Dumasia MC, Teale P. N-Deethylation and N-oxidation of etamiphylline: identification of etamiphylline-N-oxide in greyhound urine by high performance liquid chromatography–mass spectrometry. J Pharm Biomed Anal 2005; 36:1085-91. [PMID: 15620536 DOI: 10.1016/j.jpba.2004.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Revised: 08/31/2004] [Accepted: 09/01/2004] [Indexed: 11/22/2022]
Abstract
Millophyline-V, (etamiphylline camsylate) was administered intramuscularly to two racing greyhounds at a dose of 10 mg kg(-1). Unhydrolysed pre- and post-administration urine samples were extracted using mixed mode solid phase extraction (SPE) cartridges, the basic isolates derivatised as trimethylsilyl ethers and analysed by positive ion electron ionisation gas chromatography-mass spectrometry (GC/EI+/MS). The parent drug and one metabolite, N-desethyletamiphylline, were detected in urine for up to 72 h. For semi-quantification, urine samples were extracted on-line using a Prospekt sample handler. The analytes retained on the C2 SPE cartridge were eluted by the mobile phase directly on to the analytical high performance liquid chromatography column and analysed by positive ion atmospheric pressure chemical ionisation (LC/APCI+) MS in the multiple selective-ion recording mode. A major peak containing both ions (m/z) 280 and (m/z) 252 was observed. Full scan LC/APCI+/MS of the unknown indicated that the ion at (m/z) 280 was formed by the loss of an oxygen atom [MH+ -->(MH+-O)]. Samples were analysed by positive ion electrospray ionisation LC/MS on two different instruments and the unknown compound was identified as an N-oxide of the tert. nitrogen atom of the 2-(diethylamino)ethyl substituent on N7 of the theophylline nucleus. This compound has not been reported previously either as an in vivo or in vitro metabolite of etamiphylline in any species. Thermal decomposition of the N-oxide could lead to an increase the detection period of the parent drug during routine GC/MS screening of post-competition greyhound urine samples.
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Affiliation(s)
- M C Dumasia
- Horseracing Forencic Laboratory, Department of Drug Metabolism, PO Box 150, Newmarket Road, Fordham, Ely, Cambridgeshire CB7 5WP, UK.
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Highly efficient approach for characterizing nanometer-sized gold particles by capillary electrophoresis. Anal Chim Acta 2005. [DOI: 10.1016/j.aca.2004.08.052] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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