Kirwa, A.T., Williams, N.H., Mulla, M.Y. et al. (3 more authors) (2017) 'Rough guide' evanescent wave opt rode for colorimetric metalloporphyrine sensors. Talanta, 164. pp. 228-232. ISSN 0039-9140
Abstract
When films of zinc 5-(4-carboxyphenyl),10,15,20-triphenyl porphyrin (ZnTPP) are exposed to waterborne amine in pH- neutral or alkaline media, both Q- band and Soret band respond with a change of absorbance due to the donation of amine ‘lone pair’ electrons to the metalloprophyrin π orbital. However, this is difficult to reveal with a conventional spectrometer even under high amine concentration. We therefore introduce optical fibres coated with ZnTPP into a bespoke ‘light balance’ evanescent wave absorbance meter [doi:10.1016/j.snb.2016.05.065]. The light balance makes absorbance changes clearly visible under only 5 μM aqueous amine, making PVC membranes redundant. We find sensitivity is higher, and limit- of- detection lower, in the Soret band rather than the Q- band, reflecting the stronger Soret band absorbance. Also, we find that sensitivity is higher, and limit- ofdetection approximately two times lower, when rough rather than smooth fibres are used. We believe the rough fibre surface leads to enhanced evanescence, and therefore better overlap of the wave propagating in the fibre with the ZnTPP fibre cladding. We find a limit of detection to waterborne amines below 1 μM, which compares well to other sensors for waterborne amines [Korent, S.M. et.al. Anal. Bioanal. Chem. 387 (2007) 2863–2870; Algarni, S. A. et.al. Talanta 153 (2016) 107–110]. We therefore recommend ‘rough guide’ evanescent wave optrodes, in combination with sensitive ‘light balance’ detector, to succeed membrane- embedding of colorimetric sensitisers such as metalloporphyrines.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016 Elsevier. This is an author produced version of a paper subsequently published in Talanta. Uploaded in accordance with the publisher's self-archiving policy. Article available under the terms of the CC-BY-NC-ND licence (https://creativecommons.org/licenses/by-nc-nd/4.0/) |
Keywords: | Optrode; Evanescent wave; Amine; Metalloporphyrin; Lock-in |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Chemistry (Sheffield) The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Funding Information: | Funder Grant number Commonwealth Scholarship Commission KECS-2014-277 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 14 Dec 2016 11:43 |
Last Modified: | 25 Nov 2018 01:38 |
Published Version: | https://doi.org/10.1016/j.talanta.2016.11.057 |
Status: | Published |
Publisher: | Elsevier |
Refereed: | Yes |
Identification Number: | 10.1016/j.talanta.2016.11.057 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:108512 |