Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
In-Line Seawater Phosphate Detection with Ion-Exchange Membrane Reagent Delivery
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.ORCID iD: 0000-0002-3858-8466
Show others and affiliations
2018 (English)In: ACS Sensors, ISSN 2379-3694, Vol. 3, no 11, p. 2455-2462Article in journal (Refereed) Published
Abstract [en]

There is an urgent need for reliable seawater phosphate measuring tools to better assess eutrophication. Today, most accepted sensing approaches are based on the established colorimetric molybdenum blue assay. It requires one to modify the sample to strongly acidic conditions and to add various reagents, principally molybdate and reducing agent (e.g., ascorbic acid), to form a blue colored phosphate complex that is subsequently detected spectrophotometrically. The associated need for large sample and mobile phase reservoirs and mixing coils are, unfortunately, not ideally adapted for the development of operationally simple in situ sensing instruments. It is here demonstrated for the first time that the key reagents needed to achieve phosphate detection by the molybdate method may be delivered by passive counter transport across ion-exchange membranes. A cation-exchange Donnan exclusion membrane placed in contact with a sample flow (450 μm thick) is shown to provide the strongly acidic conditions (pH ∼ 1) necessary for phosphate determination. Proton transport is driven, via cation-exchange, by the high sodium content of the seawater sample. Molybdate was similarly released through an anion-exchange membrane by chloride counter transport. Consequently, an in-line flow system containing the two membrane modules in series was used for delivering both hydrogen and molybdate ions into the sample to form the desired phosphomolybdate complex for subsequent spectrophotometric detection. A linear calibration in the range of 0.1-10 μM phosphate (3-300 ppb inorganic P) was achieved, which is sufficiently attractive for environmental work. A range of seawater samples was tested and the results from this membrane delivery device showed no significant differences compared to the classical molybdate assay chosen as the reference method.

Place, publisher, year, edition, pages
American Chemical Society , 2018. Vol. 3, no 11, p. 2455-2462
Keywords [en]
inorganic phosphate, ion-exchange membrane, marine sensing, molybdate assay, molybdate delivery, seawater analysis, Ascorbic acid, Chlorine compounds, Eutrophication, Indium compounds, Ion exchange, Membranes, Molybdenum compounds, Negative ions, Positive ions, Seawater, Anion exchange membrane, Inorganic phosphates, Phosphate detections, Phosphate determination, Spectrophotometric detection, Ion exchange membranes
National Category
Chemical Sciences
Identifiers
URN: urn:nbn:se:kth:diva-247042DOI: 10.1021/acssensors.8b01096Scopus ID: 2-s2.0-85057117322OAI: oai:DiVA.org:kth-247042DiVA, id: diva2:1330103
Note

QC 20190625

Available from: 2019-06-25 Created: 2019-06-25 Last updated: 2019-06-25Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textScopus

Authority records BETA

Cuartero, Maria

Search in DiVA

By author/editor
Cuartero, Maria
By organisation
Applied Physical Chemistry
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 2 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf