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  1. Article ; Online: Minimising sample volume and run times for circular dichroism spectroscopy.

    Rodger, Alison / Chin, Timothy

    Analytical methods : advancing methods and applications

    2022  Volume 14, Issue 23, Page(s) 2337–2340

    Abstract: Circular dichroism (CD) spectroscopy is widely used to characterise chiral structures in solution, including to determine protein secondary structure content. However, protein CD experiments typically require 10-20 μg of protein. An additional challenge ... ...

    Abstract Circular dichroism (CD) spectroscopy is widely used to characterise chiral structures in solution, including to determine protein secondary structure content. However, protein CD experiments typically require 10-20 μg of protein. An additional challenge is that some proteins change their structure when their concentration is changed (they unfold or aggregate) so, particularly for protein biopharmaceuticals, it is attractive to have a range of different path lengths to hand. This paper reports the validation of demountable DMV Bio-cells of path lengths 0.5 mm, 0.2 mm and 0.125 mm, which have approximately 1 mm diameter windows, for CD spectroscopy. When complemented with a 10 cm focal length focusing lens positioned 9.5 cm in front of the sample, the signal : noise ratio of the final spectrum is equivalent to data collected on a standard cell wide enough to allow the full light beam to pass through. The DMV Bio-cells require 2-3% of the sample needed for a standard full-width cuvette and can be assembled without bubbles with the nominal path length. In addition, they are easy to clean and less likely to be chipped or broken than standard cuvettes which, together with the sample saved, compensates for their much higher price. For smaller path lengths the Jasco MSD-462 microsampling disk enabled fairly reproducible assembly at 4-7 μm depending on the sample viscosity and similarly high quality data.
    MeSH term(s) Circular Dichroism ; Protein Structure, Secondary ; Proteins/chemistry
    Chemical Substances Proteins
    Language English
    Publishing date 2022-06-16
    Publishing country England
    Document type Journal Article
    ZDB-ID 2515210-5
    ISSN 1759-9679 ; 1759-9660
    ISSN (online) 1759-9679
    ISSN 1759-9660
    DOI 10.1039/d2ay00298a
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Minimising sample volume and run times for circular dichroism spectroscopy

    Rodger, Alison / Chin, Timothy

    Analytical methods. 2022 June 16, v. 14, no. 23

    2022  

    Abstract: Circular dichroism (CD) spectroscopy is widely used to characterise chiral structures in solution, including to determine protein secondary structure content. However, protein CD experiments typically require 10–20 μg of protein. An additional challenge ... ...

    Abstract Circular dichroism (CD) spectroscopy is widely used to characterise chiral structures in solution, including to determine protein secondary structure content. However, protein CD experiments typically require 10–20 μg of protein. An additional challenge is that some proteins change their structure when their concentration is changed (they unfold or aggregate) so, particularly for protein biopharmaceuticals, it is attractive to have a range of different path lengths to hand. This paper reports the validation of demountable DMV Bio-cells of path lengths 0.5 mm, 0.2 mm and 0.125 mm, which have approximately 1 mm diameter windows, for CD spectroscopy. When complemented with a 10 cm focal length focusing lens positioned 9.5 cm in front of the sample, the signal : noise ratio of the final spectrum is equivalent to data collected on a standard cell wide enough to allow the full light beam to pass through. The DMV Bio-cells require 2–3% of the sample needed for a standard full-width cuvette and can be assembled without bubbles with the nominal path length. In addition, they are easy to clean and less likely to be chipped or broken than standard cuvettes which, together with the sample saved, compensates for their much higher price. For smaller path lengths the Jasco MSD-462 microsampling disk enabled fairly reproducible assembly at 4–7 μm depending on the sample viscosity and similarly high quality data.
    Keywords biopharmaceuticals ; circular dichroism spectroscopy ; prices ; protein secondary structure ; viscosity
    Language English
    Dates of publication 2022-0616
    Size p. 2337-2340.
    Publishing place The Royal Society of Chemistry
    Document type Article
    ZDB-ID 2515210-5
    ISSN 1759-9679 ; 1759-9660
    ISSN (online) 1759-9679
    ISSN 1759-9660
    DOI 10.1039/d2ay00298a
    Database NAL-Catalogue (AGRICOLA)

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  3. Article: Spectroscopic fingerprints of valence and spin states in manganese oxides and fluorides

    Qiao, Ruimin / Chin, Timothy / Harris, Stephen J / Yan, Shishen / Yang, Wanli

    Current applied physics. 2013 May, v. 13, no. 3

    2013  

    Abstract: We performed a systematic study of soft X-ray absorption spectroscopy in various manganese oxides and fluorides. Both Mn L-edges and ligand (O and F) K-edges are presented and compared with each other. Despite the distinct crystal structure and covalent/ ... ...

    Abstract We performed a systematic study of soft X-ray absorption spectroscopy in various manganese oxides and fluorides. Both Mn L-edges and ligand (O and F) K-edges are presented and compared with each other. Despite the distinct crystal structure and covalent/ionic nature in different systems, the Mn-L spectra fingerprint the Mn valence and spin states through spectral lineshape and energy position consistently and evidently. The clear O- and F-K pre-edge features in our high resolution spectra enable a quantitative definition of the molecular orbital diagram with different Mn valence. In addition, while the binding energy difference of the O-1s core electrons leads to a small shift of the O-K leading edges between trivalent and quadrivalent manganese oxides, a significant edge shift, with an order of magnitude larger in energy, was found between divalent and trivalent compounds, which is attributed to the spin exchange stabilization of half-filled 3d system. This shift is much enhanced in the ionic fluoride system. This work provides the spectroscopic foundation for further studies of complicated Mn compounds.
    Keywords X-radiation ; absorption ; crystal structure ; electrons ; energy ; fluorides ; manganese ; manganese oxides ; spectroscopy
    Language English
    Dates of publication 2013-05
    Size p. 544-548.
    Publishing place Elsevier B.V.
    Document type Article
    ISSN 1567-1739
    DOI 10.1016/j.cap.2012.09.017
    Database NAL-Catalogue (AGRICOLA)

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  4. Article: Spectroscopic fingerprints of valence and spin states in manganese oxides and fluorides

    Qiao, Ruimin / Chin, Timothy / Harris, Stephen J. / Yan, Shishen / Yang, Wanli

    Current applied physics

    Volume v. 13,, Issue no. 3

    Abstract: We performed a systematic study of soft X-ray absorption spectroscopy in various manganese oxides and fluorides. Both Mn L-edges and ligand (O and F) K-edges are presented and compared with each other. Despite the distinct crystal structure and covalent/ ... ...

    Abstract We performed a systematic study of soft X-ray absorption spectroscopy in various manganese oxides and fluorides. Both Mn L-edges and ligand (O and F) K-edges are presented and compared with each other. Despite the distinct crystal structure and covalent/ionic nature in different systems, the Mn-L spectra fingerprint the Mn valence and spin states through spectral lineshape and energy position consistently and evidently. The clear O- and F-K pre-edge features in our high resolution spectra enable a quantitative definition of the molecular orbital diagram with different Mn valence. In addition, while the binding energy difference of the O-1s core electrons leads to a small shift of the O-K leading edges between trivalent and quadrivalent manganese oxides, a significant edge shift, with an order of magnitude larger in energy, was found between divalent and trivalent compounds, which is attributed to the spin exchange stabilization of half-filled 3d system. This shift is much enhanced in the ionic fluoride system. This work provides the spectroscopic foundation for further studies of complicated Mn compounds.
    Keywords absorption ; fluorides ; manganese oxides ; crystal structure ; spectroscopy ; manganese ; energy ; electrons ; X-radiation
    Language English
    Document type Article
    ISSN 1567-1739
    Database AGRIS - International Information System for the Agricultural Sciences and Technology

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