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Lagator M, Berrueta Razo I, Royle T, Lockyer NP. Sensitivity enhancement using chemically reactive gas cluster ion beams in secondary ion mass spectrometry (SIMS). SURF INTERFACE ANAL 2022. [DOI: 10.1002/sia.7054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Matija Lagator
- Department of Chemistry, Photon Science Institute University of Manchester Manchester UK
| | - Irma Berrueta Razo
- Department of Chemistry, Photon Science Institute University of Manchester Manchester UK
| | - Thomas Royle
- Department of Chemistry, Photon Science Institute University of Manchester Manchester UK
| | - Nicholas P. Lockyer
- Department of Chemistry, Photon Science Institute University of Manchester Manchester UK
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2
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Shard AG, Miisho A, Vorng J, Havelund R, Gilmore IS, Aoyagi S. A two‐point calibration method for quantifying organic binary mixtures using secondary ion mass spectrometry in the presence of matrix effects. SURF INTERFACE ANAL 2021. [DOI: 10.1002/sia.7042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | - Ako Miisho
- Kobelco Research Institute, Inc. Kobe Japan
| | | | - Rasmus Havelund
- National Physical Laboratory Teddington UK
- Department of Medical Physics Vejle Hospital Vejle Denmark
| | | | - Satoka Aoyagi
- Department of Materials and Life Science Seikei University Tokyo Japan
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Lorenz M, Zhang J, Shard AG, Vorng JL, Rakowska PD, Gilmore IS. Method for Molecular Layer Deposition Using Gas Cluster Ion Beam Sputtering with Example Application In Situ Matrix-Enhanced Secondary Ion Mass Spectrometry. Anal Chem 2021; 93:3436-3444. [PMID: 33571411 DOI: 10.1021/acs.analchem.0c04680] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We introduce a technique for the directed transfer of molecules from an adjacent reservoir onto a sample surface inside the vacuum chamber of a ToF-SIMS instrument using gas cluster ion beam (GCIB) sputtering. An example application for in situ matrix-enhanced secondary ion mass spectrometry (ME SIMS) is provided. This protocol has attractive features since most modern SIMS instruments are equipped with a GCIB gun. No solvents are required that would delocalize analytes at the surface, and the transfer of matrix molecules can be interlaced with SIMS depth profiling and 3D imaging sputtering and analysis cycles, which is not possible with conventional ME SIMS strategies. The amount of molecular deposition can be finely tuned, which is important for such a surface sensitive technique as SIMS. To demonstrate the concept, we used 2,5-DHB as a matrix for the enhancement of three drug molecules embedded in a tissue homogenate. By automatic operation of sputter deposition and erosion (cleanup) cycles, depth profiling could be achieved with ME SIMS with good repeatability (<4% RSD). Furthermore, we explored several different matrix compounds, including α-CHCA and aqueous solutions of Brønsted acids (formic acid) and 3-nitrobenzonitrile, a volatile compound known to spontaneously produce ions. The latter two matrix compounds were applied at cryogenic measurement conditions, which extend the range of matrices applicable for ME SIMS. Enhancement ratios range from 2 to 13, depending on the analytes and matrix. The method works in principle, but enhancement ratios for the drug molecules are rather limited at this point. Further study and optimization is needed, and the technique introduced here provides a tool to perform systematic studies of matrix compounds and experimental conditions for their potential for signal enhancement in ME SIMS.
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Affiliation(s)
- Matthias Lorenz
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
| | - Junting Zhang
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
| | - Alexander G Shard
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
| | - Jean-Luc Vorng
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
| | - Paulina D Rakowska
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
| | - Ian S Gilmore
- National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom
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4
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SIMS of organic layers with unknown matrix parameters: Locating the interface in dual beam argon gas cluster depth profiles. SURF INTERFACE ANAL 2019. [DOI: 10.1002/sia.6701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Starr NJ, Abdul Hamid K, Wibawa J, Marlow I, Bell M, Pérez-García L, Barrett DA, Scurr DJ. Enhanced vitamin C skin permeation from supramolecular hydrogels, illustrated using in situ ToF-SIMS 3D chemical profiling. Int J Pharm 2019; 563:21-29. [PMID: 30885652 DOI: 10.1016/j.ijpharm.2019.03.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 03/12/2019] [Accepted: 03/14/2019] [Indexed: 01/10/2023]
Abstract
Vitamin C (ascorbic acid) is a naturally occurring, powerful anti-oxidant with the potential to deliver numerous benefits to the skin when applied topically. However, topical use of this compound is currently restricted by an instability in traditional formulations and the delivery and eventual fate of precursor compounds has been largely unexplored. Time of flight secondary ion mass spectrometry (ToF-SIMS) is an emerging technique in the field of skin research and offers detailed chemical analysis, with high mass and spatial resolution, as well as profiling capabilities that allow analysis as a function of sample depth. This work demonstrates the successful use of ToF-SIMS to obtain, in situ, accurate 3D permeation profiles of both ascorbic acid and a popular precursor, ascorbyl glucoside, from ex vivo porcine skin. The significant permeation enhancing effect of a supramolecular hydrogel formulation, produced from an amphiphilic gemini imidazolium-based surfactant, was also demonstrated for both compounds. Using ToF-SIMS, it was also possible to detect and track the breakdown of ascorbyl glucoside into ascorbic acid, elucidating the ability of the hydrogel formulation to preserve this important conversion until the targeted epidermal layer has been reached. This work demonstrates the potential of ToF-SIMS to provide 3D permeation profiles collected in situ from ex vivo tissue samples, offering detailed analysis on compound localisation and degradation. This type of analysis has significant advantages in the area of skin permeation, but can also be readily translated to other tissue types.
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Affiliation(s)
- Nichola J Starr
- Advanced Materials and Healthcare Technologies, School of Pharmacy, University of Nottingham, NG7 2RD, UK
| | - Khuriah Abdul Hamid
- Advanced Materials and Healthcare Technologies, School of Pharmacy, University of Nottingham, NG7 2RD, UK
| | | | - Ian Marlow
- Walgreens Boots Alliance, Nottingham NG90 1BS, UK
| | - Mike Bell
- Walgreens Boots Alliance, Nottingham NG90 1BS, UK
| | - Luïsa Pérez-García
- Advanced Materials and Healthcare Technologies, School of Pharmacy, University of Nottingham, NG7 2RD, UK
| | - David A Barrett
- Advanced Materials and Healthcare Technologies, School of Pharmacy, University of Nottingham, NG7 2RD, UK
| | - David J Scurr
- Advanced Materials and Healthcare Technologies, School of Pharmacy, University of Nottingham, NG7 2RD, UK.
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Goodwin CM, Voras ZE, Beebe TP. Gas-cluster ion sputtering: Effect on organic layer morphology. JOURNAL OF VACUUM SCIENCE & TECHNOLOGY. A, VACUUM, SURFACES, AND FILMS : AN OFFICIAL JOURNAL OF THE AMERICAN VACUUM SOCIETY 2018; 36:051507. [PMID: 30078936 PMCID: PMC6063752 DOI: 10.1116/1.5044643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 07/03/2018] [Accepted: 07/11/2018] [Indexed: 06/08/2023]
Abstract
Analysis of the surface of thin Irganox 1010 films before and after sputtering with an argon gas-cluster ion beam was performed with AFM and XPS to determine the effect that Zalar rotation has on the chemistry and morphology of the surface. The analysis is based on the change in roughness of the surface by comparing the same location on the surface before and after sputtering. The ion beam used was an Ar n + of size n = 1000 and energy 4 keV. The XPS analysis agreed with previous results in which the ion beam did not cause measurable accumulation of damaged material. Based on the AFM results, the Irganox 1010 surface became rougher as a result of ion sputtering, and the degree of roughening was quantified, as was the sputter rate. Furthermore, Zalar rotation during ion sputtering did not have a significant effect on surface roughening, surprisingly.
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Affiliation(s)
- Christopher M Goodwin
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716
| | - Zachary E Voras
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716
| | - Thomas P Beebe
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716
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Havelund R, Seah MP, Tiddia M, Gilmore IS. SIMS of Organic Materials-Interface Location in Argon Gas Cluster Depth Profiles Using Negative Secondary Ions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2018; 29:774-785. [PMID: 29468500 PMCID: PMC5889422 DOI: 10.1007/s13361-018-1905-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/25/2018] [Accepted: 01/25/2018] [Indexed: 06/08/2023]
Abstract
A procedure has been established to define the interface position in depth profiles accurately when using secondary ion mass spectrometry and the negative secondary ions. The interface position varies strongly with the extent of the matrix effect and so depends on the secondary ion measured. Intensity profiles have been measured at both fluorenylmethyloxycarbonyl-L-pentafluorophenylalanine (FMOC) to Irganox 1010 and Irganox 1010 to FMOC interfaces for many secondary ions. These profiles show separations of the two interfaces that vary over some 10 nm depending on the secondary ion selected. The shapes of these profiles are strongly governed by matrix effects, slightly weakened by a long wavelength roughening. The matrix effects are separately measured using homogeneous, known mixtures of these two materials. Removal of the matrix and roughening effects give consistent compositional profiles for all ions that are described by an integrated exponentially modified Gaussian (EMG) profile. Use of a simple integrated Gaussian may lead to significant errors. The average interface positions in the compositional profiles are determined to standard uncertainties of 0.19 and 0.14 nm, respectively, using the integrated EMG function. Alternatively, and more simply, it is shown that interface positions and profiles may be deduced from data for several secondary ions with measured matrix factors by simply extrapolating the result to Ξ = 0. Care must be taken in quoting interface resolutions since those measured for predominantly Gaussian interfaces with Ξ above or below zero, without correction, appear significantly better than the true resolution. Graphical Abstract ᅟ.
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Affiliation(s)
- R Havelund
- National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK.
| | - M P Seah
- National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK
| | - M Tiddia
- Universita degli Studi di Cagliari, Dipartimento di Fisica S. P. Monserrato, Sestu Km 0.700, 09042, Monserrato, CA, Italy
| | - I S Gilmore
- National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK
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Seah M. Analytic function to describe interfaces and resolution consistency in sputter depth profiling. SURF INTERFACE ANAL 2017. [DOI: 10.1002/sia.6347] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- M.P. Seah
- Chemical, Medical and Environmental Science Division; National Physical Laboratory; Teddington Middlesex TW11 0LW UK
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9
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Trapping gases in metal-organic frameworks with a selective surface molecular barrier layer. Nat Commun 2016; 7:13871. [PMID: 27958274 PMCID: PMC5159845 DOI: 10.1038/ncomms13871] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 11/07/2016] [Indexed: 11/24/2022] Open
Abstract
The main challenge for gas storage and separation in nanoporous materials is that many molecules of interest adsorb too weakly to be effectively retained. Instead of synthetically modifying the internal surface structure of the entire bulk—as is typically done to enhance adsorption—here we show that post exposure of a prototypical porous metal-organic framework to ethylenediamine can effectively retain a variety of weakly adsorbing molecules (for example, CO, CO2, SO2, C2H4, NO) inside the materials by forming a monolayer-thick cap at the external surface of microcrystals. Furthermore, this capping mechanism, based on hydrogen bonding as explained by ab initio modelling, opens the door for potential selectivity. For example, water molecules are shown to disrupt the hydrogen-bonded amine network and diffuse through the cap without hindrance and fully displace/release the retained small molecules out of the metal-organic framework at room temperature. These findings may provide alternative strategies for gas storage, delivery and separation. Metal-organic frameworks are extensively studied for gas storage applications, but one potential limitation is their relatively weak adsorption of gases. Here, the authors report that the exposure of metal-organic frameworks to ethylenediamine forms a monolayer thick cap which improves gas molecule retention.
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Seah MP, Havelund R, Gilmore IS. Systematic Temperature Effects in the Argon Cluster Ion Sputter Depth Profiling of Organic Materials Using Secondary Ion Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:1411-1418. [PMID: 27106601 DOI: 10.1007/s13361-016-1401-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/30/2016] [Accepted: 03/31/2016] [Indexed: 06/05/2023]
Abstract
A study is presented of the effects of sample temperature on the sputter depth profiling of two organic materials, NPB (N,N'-Di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine) and Irganox 1010, using a 5 keV Ar2000 (+) cluster ion beam and analysis by secondary ion mass spectrometry. It is shown that at low temperatures, the yields increase slowly with temperature in accordance with the Universal Sputtering Yield equation where the energy term is now modified by Trouton's rule. This occurs up to a transition temperature, T T, which is, in turn, approximately 0.8T M, where T M is the sample melting temperature in Kelvin. For NPB and Irganox 1010, these transition temperatures are close to 15 °C and 0 °C, respectively. Above this temperature, the rate of increase of the sputtering yield rises by an order of magnitude. During sputtering, the depth resolution also changes with temperature with a very small change occurring below T T. At higher temperatures, the depth resolution improves but then rapidly degrades, possibly as a result first of local crater surface diffusion and then of bulk inter-diffusion. The secondary ion spectra also change with temperature with the intensities of the molecular entities increasing least. This agrees with a model in which the molecular entities arise near the crater rim. It is recommended that for consistent results, measurements for organic materials are always made at temperatures significantly below T T or 0.8 T M, and this is generally below room temperature. Graphical Abstract ᅟ.
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Affiliation(s)
- Martin P Seah
- Surface and Nanoanalysis, National Physical Laboratory, Teddington, Middlesex, TW11 0LW, England, UK.
| | - Rasmus Havelund
- Surface and Nanoanalysis, National Physical Laboratory, Teddington, Middlesex, TW11 0LW, England, UK
| | - Ian S Gilmore
- Surface and Nanoanalysis, National Physical Laboratory, Teddington, Middlesex, TW11 0LW, England, UK
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