Characterization of meta-Cresol Purple for spectrophotometric pH measurements in saline and hypersaline media at sub-zero temperatures
Accurate pH measurements in polar waters and sea ice brines require pH indicator dyes characterized at near-zero and below-zero temperatures and high salinities. We present experimentally determined physical and chemical characteristics of purified meta-Cresol Purple (mCP) pH indicator dye suitable...
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ftsouthampton:oai:eprints.soton.ac.uk:411149 2023-07-30T04:06:46+02:00 Characterization of meta-Cresol Purple for spectrophotometric pH measurements in saline and hypersaline media at sub-zero temperatures Loucaides, Socratis Rerolle, Victoire M.C. Papadimitriou, Stathys Kennedy, Hilary Mowlem, Matthew C. Dickson, Andrew G. Gledhill, Martha Achterberg, Eric P. 2017-05-30 text https://eprints.soton.ac.uk/411149/ https://eprints.soton.ac.uk/411149/1/art_3A10.1038_2Fs41598_017_02624_0.pdf en English eng https://eprints.soton.ac.uk/411149/1/art_3A10.1038_2Fs41598_017_02624_0.pdf Loucaides, Socratis, Rerolle, Victoire M.C., Papadimitriou, Stathys, Kennedy, Hilary, Mowlem, Matthew C., Dickson, Andrew G., Gledhill, Martha and Achterberg, Eric P. (2017) Characterization of meta-Cresol Purple for spectrophotometric pH measurements in saline and hypersaline media at sub-zero temperatures. Scientific Reports, 7 (1), [2481]. (doi:10.1038/s41598-017-02624-0 <http://dx.doi.org/10.1038/s41598-017-02624-0>). cc_by_4 Article PeerReviewed 2017 ftsouthampton https://doi.org/10.1038/s41598-017-02624-0 2023-07-09T22:15:36Z Accurate pH measurements in polar waters and sea ice brines require pH indicator dyes characterized at near-zero and below-zero temperatures and high salinities. We present experimentally determined physical and chemical characteristics of purified meta-Cresol Purple (mCP) pH indicator dye suitable for pH measurements in seawater and conservative seawater-derived brines at salinities (S) between 35 and 100 and temperatures (T) between their freezing point and 298.15 K (25 °C). Within this temperature and salinity range, using purified mCP and a novel thermostated spectrophotometric device, the pH on the total scale (pHT) can be calculated from direct measurements of the absorbance ratio R of the dye in natural samples as pHT=−log(kT2e2)+log(R−e11−Re3e2) Based on the mCP characterization in these extended conditions, the temperature and salinity dependence of the molar absorptivity ratios and − log(kT2e2) of purified mCP is described by the following functions: e1 = −0.004363 + 3.598 × 10−5T, e3/e2 = −0.016224 + 2.42851 × 10−4T + 5.05663 × 10−5(S − 35), and − log(kT2e2) = −319.8369 + 0.688159 S −0.00018374 S2 + (10508.724 − 32.9599 S + 0.059082S2) T−1 + (55.54253 − 0.101639 S) ln T −0.08112151T. This work takes the characterisation of mCP beyond the currently available ranges of 278.15 K ≤ T ≤ 308.15 K and 20 ≤ S ≤ 40 in natural seawater, thereby allowing high quality pHT measurements in polar systems. Article in Journal/Newspaper Sea ice University of Southampton: e-Prints Soton Scientific Reports 7 1 |
institution |
Open Polar |
collection |
University of Southampton: e-Prints Soton |
op_collection_id |
ftsouthampton |
language |
English |
description |
Accurate pH measurements in polar waters and sea ice brines require pH indicator dyes characterized at near-zero and below-zero temperatures and high salinities. We present experimentally determined physical and chemical characteristics of purified meta-Cresol Purple (mCP) pH indicator dye suitable for pH measurements in seawater and conservative seawater-derived brines at salinities (S) between 35 and 100 and temperatures (T) between their freezing point and 298.15 K (25 °C). Within this temperature and salinity range, using purified mCP and a novel thermostated spectrophotometric device, the pH on the total scale (pHT) can be calculated from direct measurements of the absorbance ratio R of the dye in natural samples as pHT=−log(kT2e2)+log(R−e11−Re3e2) Based on the mCP characterization in these extended conditions, the temperature and salinity dependence of the molar absorptivity ratios and − log(kT2e2) of purified mCP is described by the following functions: e1 = −0.004363 + 3.598 × 10−5T, e3/e2 = −0.016224 + 2.42851 × 10−4T + 5.05663 × 10−5(S − 35), and − log(kT2e2) = −319.8369 + 0.688159 S −0.00018374 S2 + (10508.724 − 32.9599 S + 0.059082S2) T−1 + (55.54253 − 0.101639 S) ln T −0.08112151T. This work takes the characterisation of mCP beyond the currently available ranges of 278.15 K ≤ T ≤ 308.15 K and 20 ≤ S ≤ 40 in natural seawater, thereby allowing high quality pHT measurements in polar systems. |
format |
Article in Journal/Newspaper |
author |
Loucaides, Socratis Rerolle, Victoire M.C. Papadimitriou, Stathys Kennedy, Hilary Mowlem, Matthew C. Dickson, Andrew G. Gledhill, Martha Achterberg, Eric P. |
spellingShingle |
Loucaides, Socratis Rerolle, Victoire M.C. Papadimitriou, Stathys Kennedy, Hilary Mowlem, Matthew C. Dickson, Andrew G. Gledhill, Martha Achterberg, Eric P. Characterization of meta-Cresol Purple for spectrophotometric pH measurements in saline and hypersaline media at sub-zero temperatures |
author_facet |
Loucaides, Socratis Rerolle, Victoire M.C. Papadimitriou, Stathys Kennedy, Hilary Mowlem, Matthew C. Dickson, Andrew G. Gledhill, Martha Achterberg, Eric P. |
author_sort |
Loucaides, Socratis |
title |
Characterization of meta-Cresol Purple for spectrophotometric pH measurements in saline and hypersaline media at sub-zero temperatures |
title_short |
Characterization of meta-Cresol Purple for spectrophotometric pH measurements in saline and hypersaline media at sub-zero temperatures |
title_full |
Characterization of meta-Cresol Purple for spectrophotometric pH measurements in saline and hypersaline media at sub-zero temperatures |
title_fullStr |
Characterization of meta-Cresol Purple for spectrophotometric pH measurements in saline and hypersaline media at sub-zero temperatures |
title_full_unstemmed |
Characterization of meta-Cresol Purple for spectrophotometric pH measurements in saline and hypersaline media at sub-zero temperatures |
title_sort |
characterization of meta-cresol purple for spectrophotometric ph measurements in saline and hypersaline media at sub-zero temperatures |
publishDate |
2017 |
url |
https://eprints.soton.ac.uk/411149/ https://eprints.soton.ac.uk/411149/1/art_3A10.1038_2Fs41598_017_02624_0.pdf |
genre |
Sea ice |
genre_facet |
Sea ice |
op_relation |
https://eprints.soton.ac.uk/411149/1/art_3A10.1038_2Fs41598_017_02624_0.pdf Loucaides, Socratis, Rerolle, Victoire M.C., Papadimitriou, Stathys, Kennedy, Hilary, Mowlem, Matthew C., Dickson, Andrew G., Gledhill, Martha and Achterberg, Eric P. (2017) Characterization of meta-Cresol Purple for spectrophotometric pH measurements in saline and hypersaline media at sub-zero temperatures. Scientific Reports, 7 (1), [2481]. (doi:10.1038/s41598-017-02624-0 <http://dx.doi.org/10.1038/s41598-017-02624-0>). |
op_rights |
cc_by_4 |
op_doi |
https://doi.org/10.1038/s41598-017-02624-0 |
container_title |
Scientific Reports |
container_volume |
7 |
container_issue |
1 |
_version_ |
1772819674660077568 |