The effect of electrolytes on pH measurements via glass electrodes is explored with solutions buffered at pH 7 (phosphate and cacodylate). Salt and buffer concentrations are varied. Direct and reverse Hofmeister effects are observed. The phenomena are significant for salt concentrations above 0.1 M and for buffer concentrations below 20 mM. Changes in measured pH show up most strongly with anions. They can be related to the usual physicochemical parameters (anion molar volumes, molar refractivity, and surface tensions) that are characteristic of Hofmeister series. They correlate strongly with anionic excess polarizabilities; this suggests the involvement of non-electrostatic, or dispersion, forces acting on ions. These forces contribute to ionic adsorption at the glass electrode surface, and to the liquid junction potential.

Specific Anion Effects on Glass Electrode pH Measurements of Buffer Solutions: Bulk and Surface Phenomena / Salis, A; PINNA M., C; Bilanicova, D; Monduzzi, M; LO NOSTRO, Pierandrea; Ninham, B. W.. - In: JOURNAL OF PHYSICAL CHEMISTRY. B, CONDENSED MATTER, MATERIALS, SURFACES, INTERFACES & BIOPHYSICAL. - ISSN 1520-6106. - STAMPA. - 110:(2006), pp. 2949-2956. [10.1021/jp0546296]

Specific Anion Effects on Glass Electrode pH Measurements of Buffer Solutions: Bulk and Surface Phenomena

LO NOSTRO, PIERANDREA;
2006

Abstract

The effect of electrolytes on pH measurements via glass electrodes is explored with solutions buffered at pH 7 (phosphate and cacodylate). Salt and buffer concentrations are varied. Direct and reverse Hofmeister effects are observed. The phenomena are significant for salt concentrations above 0.1 M and for buffer concentrations below 20 mM. Changes in measured pH show up most strongly with anions. They can be related to the usual physicochemical parameters (anion molar volumes, molar refractivity, and surface tensions) that are characteristic of Hofmeister series. They correlate strongly with anionic excess polarizabilities; this suggests the involvement of non-electrostatic, or dispersion, forces acting on ions. These forces contribute to ionic adsorption at the glass electrode surface, and to the liquid junction potential.
2006
110
2949
2956
Salis, A; PINNA M., C; Bilanicova, D; Monduzzi, M; LO NOSTRO, Pierandrea; Ninham, B. W.
File in questo prodotto:
File Dimensione Formato  
pH2006.pdf

Accesso chiuso

Tipologia: Versione finale referata (Postprint, Accepted manuscript)
Licenza: Tutti i diritti riservati
Dimensione 113.22 kB
Formato Adobe PDF
113.22 kB Adobe PDF   Richiedi una copia

I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/213040
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 101
  • ???jsp.display-item.citation.isi??? 97
social impact