Graphite Screen-Printed Electrodes Applied for the Accurate and Reagentless Sensing of pH
AuthorsGaldino, Flávia E.
Smith, Jamie P.
Kwamou, Sophie I.
Kampouris, Dimitrios K.
Smith, Graham C.
Bonacin, Juliano A.
Banks, Craig E.
AffiliationUniversity of Campinas, Brazil (Galdino, Bonacin), Manchester Metropolitain University (JP Smith, Kampouris, Banks), Universite Paris Est Creteil, France (Kwamou), University of Alicante, Spain (Inestia), University of Chester (GC Smith)
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AbstractA reagentless pH sensor based upon disposable and economical graphite screen-printed electrodes (GSPEs) is demonstrated for the first time. The voltammetric pH sensor utilises GSPEs which are chemically pre-treated to form surface immobilised oxygenated species that when their redox behaviour is monitored, give a Nernstian response over a large pH range (1-13). An excellent experimental correlation is observed between the voltammetric potential and pH over the entire pH range of 1-13, such a response is not usually expected but rather deviation from linearity is encountered at alkaline pH values; absence of this has previously been attributed to a change in pKa value of surface immobilised groups. This non-deviation, which is observed here in the case of our facile produced reagentless pH sensor and also reported in the literature for pH sensitive compounds immobilized upon carbon electrodes/surfaces,where a linear response is observed over the entire pH range, is explained alternatively for the first time. The performance of the GSPE pH sensor is directly compared with a glass pH probe and applied to the measurement of pH in real samples where an excellent correlation between the two protocols is observed validating the proposed GSPE pH sensor.
CitationGaldino, F. E., Smith, J. P., Kwamou, S. I., Kampouris, D. K., Iniesta, J., Smith, G. C., . . . Banks, C. E. (2015). Graphite Screen-Printed Electrodes Applied for the Accurate and Reagentless Sensing of pH. Analytical Chemistry, 87(23), 11666-11672. doi:10.1021/acs.analchem.5b01236
PublisherAmerican Chemical Society
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