New solid state phosphate sensitive electrodes for routine environmental monitoring
Author(s)
Fikru Tafesse*
ABSTRACT
Highly selective and sensitive phosphate sensors have been fabricated by constructing a solid membrane disk consisting of variable mixtures of aluminium powder (Al), aluminium phosphate (AlPO4) and powdered copper (Cu). Both binary and ternary electrode systems are produced. The ternary membranes exhibit greater selectivity over a wide range of concentrations. The ternary electrode with the composition 25% AlPO4, 25% Cu and 50% Al was selected as our preferred electrode. The newly fabricated ternary membrane phosphate selective electrodes exhibited linear potential response in the concentration range of 1.0 × 10?1 to 1.0 × 10?6 mol L?1. The electrodes also exhibit a fast response time of <60 s. Their detection limit is lower than 1.0 × 10?6 mol L?1. The unique feature of the described electrodes is their ability to maintain a steady and reproducible response in the absence of an ionic strength control. The electrodes have a long lifetime and can be stored in air when not in use.
Highly selective and sensitive phosphate sensors have been fabricated by constructing a solid membrane disk consisting of variable mixtures of aluminium powder (Al), aluminium phosphate (AlPO4) and powdered copper (Cu). Both binary and ternary electrode systems are produced. The ternary membranes exhibit greater selectivity over a wide range of concentrations. The ternary electrode with the composition 25% AlPO4, 25% Cu and 50% Al was selected as our preferred electrode. The newly fabricated ternary membrane phosphate selective electrodes exhibited linear potential response in the concentration range of 1.0 × 10?1 to 1.0 × 10?6 mol L?1. The electrodes also exhibit a fast response time of <60 s. Their detection limit is lower than 1.0 × 10?6 mol L?1. The unique feature of the described electrodes is their ability to maintain a steady and reproducible response in the absence of an ionic strength control. The electrodes have a long lifetime and can be stored in air when not in use.
KEYWORDS
Phosphate selective electrodes; selectivity coefficient; ionic strength; inorganic phosphate, environmental monitoring.
Phosphate selective electrodes; selectivity coefficient; ionic strength; inorganic phosphate, environmental monitoring.
Cite this paper
nullTafesse, F. (2012) New solid state phosphate sensitive electrodes for routine environmental monitoring. Open Journal of Applied Sciences, 2, 128-131. doi: 10.4236/ojapps.2012.24B031.
nullTafesse, F. (2012) New solid state phosphate sensitive electrodes for routine environmental monitoring. Open Journal of Applied Sciences, 2, 128-131. doi: 10.4236/ojapps.2012.24B031.
References
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[1] K. Robards, I. D. Mckelvie, R. L. Benson, P. J. Worsfold, N. J. Brundell, H. Casey; Determination of carbon, phosphorus, nitrogen and silicon species in water. Anal. Chim. Acta. 287 (1994) 147-190. [2] G. Hanrahan, M. Gledhill, W. A. House, P. J. Worsfold; Evaluation of phosphorus concentrations in relation to annual and seasonal physico-chemical water quality parameters in a UK chalk stream. Water Res., 37(15) (2003) 3579-3589 [3] L. Cisse, T. Mrabet; World phosphate production: Overview and prospects. Phosphorus Research Bulletin, 15 (2004) 21-25. [4] R. S. Malek, R. S. Kuntzman, D. M. Barret; Photosensitive potassium-titanyl phosphate laser vaporization of the benign obstructive prostate: observations on long term outcomes. J. Urol. 174, 4(1) (2005) 1344-1348. [5] S. M. Yarema, D. Milam; Gain saturation in phosphate laser glasses. IEEE journal of Quantum Electronics. QE-18(11) (1982) 1941-1946. [6] S. Jiang, J. D. Myers, D. L. Rhonehouse, M. Myers, R. E. Belford, S. J. Hamlin, R. E. Belford; Laser and thermal performance of a new Erbium doped phosphate laser glass. SPIE Vol. 2138, longer wavelengths lasers and applications (1994) 1-5. [7] E. Bakker, E. Pretsch; Potentiometry at trace levels. Trends in analytical chemistry, 20(1), (2001) 11-19. [8] D. P. Quan, L. T. Duan, C. X. Quang, P. H. Viet; A conducting polymer based solid-contact potassium selective electrode. Analytical Sciences. Vol. 17 Supplement (2001) i749-i752. [9] A. Cadogan, Z. Gao, A. Lewenstam, A. Ivaska; All-Solid-State-Sodium-Selective electrode based on a calixarene ionophore in a poly(vinyl chloride) membrane with a polypyrrole solid contact. Anal. Chem. 64 (1992) 2496-2501. [10] G. Somer, S. Kalayci, I. Basak; Preparation of a new solid state fluoride ion selective electrodes and application. Talanta, 80 (2010) 1129-1132. [11] G. Ekemekci, S. Kalayci, G Somer; A solid state hydroxide ion selective electrode for the measurement of high pH values. Sensors and Actuators, B 101, (2004) 260-264.