Abstract
A new optical pH measurement method will be presented. It is based on the acid-base equilibrium (emeraldine salt to emeraldine base transition) of water dispersions of polyaniline nanoparticles [1-4].
The determination of pH is possible between pH 8-10.5 (delta pH=0.1) with a relative standard deviation of 1-2% (800 nm; n=7; peak area) by combining UV-vis spectroscopy with an automated sequential injection analysis (SIA) system. Alternatively, an optical fibre probe (400-700 nm) can used for batch pH measurements. In this case, pH measurements are possible between pH 6-10 (580 nm).
Redox electrochemistry with the water dispersion of polyaniline nanoparticles can also be carried out in the solution phase (pH 6) in the presence of the Fe(CN)6(3-)/(4-) and Fe(C2O4)3(3-)/(4-) redox couples. It is shown with UV-vis spectroscopy that polyaniline can be converted between the leucoemeraldine base, emeraldine salt and pernigraniline base forms.
References:
[1] B. Wessling, D. Srinivasan, G. Rangarajan, T. Mietzner and W. Lennartz, Eur. Phys. J., E2 (2000) 2007.
[2] B. Wessling, Synth. Met., 135-136 (2003) 265-267.
[3] www.ormecon.de
[4] www.panipol.com
The determination of pH is possible between pH 8-10.5 (delta pH=0.1) with a relative standard deviation of 1-2% (800 nm; n=7; peak area) by combining UV-vis spectroscopy with an automated sequential injection analysis (SIA) system. Alternatively, an optical fibre probe (400-700 nm) can used for batch pH measurements. In this case, pH measurements are possible between pH 6-10 (580 nm).
Redox electrochemistry with the water dispersion of polyaniline nanoparticles can also be carried out in the solution phase (pH 6) in the presence of the Fe(CN)6(3-)/(4-) and Fe(C2O4)3(3-)/(4-) redox couples. It is shown with UV-vis spectroscopy that polyaniline can be converted between the leucoemeraldine base, emeraldine salt and pernigraniline base forms.
References:
[1] B. Wessling, D. Srinivasan, G. Rangarajan, T. Mietzner and W. Lennartz, Eur. Phys. J., E2 (2000) 2007.
[2] B. Wessling, Synth. Met., 135-136 (2003) 265-267.
[3] www.ormecon.de
[4] www.panipol.com
| Original language | English |
|---|---|
| Publication status | Published - 2005 |
| MoE publication type | O2 Other |
| Event | Mátrafüred 2005, Internation Conference on Electrochemical Sensors - Mátrafüred, Hungary Duration: 13 Nov 2005 → 18 Nov 2005 |
Conference
| Conference | Mátrafüred 2005, Internation Conference on Electrochemical Sensors |
|---|---|
| Country/Territory | Hungary |
| City | Mátrafüred |
| Period | 13/11/05 → 18/11/05 |
Keywords
- Polyaniline
- Dispersion
- Protonation constants
- pH sensitivity