Two improved systems for the determination of the difference in pH between two solutions at the same temperature are described, both of which have a long-term stability of ±1 × 10-4 pH unit and a peak-to-peak noise level of 5 × 10-5 pH unit when operated in the differential mode. The cells are constructed of Delrin which has been found to be inert in biological fluids. These cells, with a volume of 1 ml, can be electrically connected to each other via a dialysis membrane and are thermostated during the duration of the pH measurements to ±0.01°C. In a second configuration, combination microelectrodes are inserted into each cell; thus the dialysis membrane is not necessary. To demonstrate the application of these systems to reactions of biological interest where pH changes occur, we investigated the hexokinase-catalyzed reaction between ATP and glucose in a phosphate buffer. The concentrations of glucose determined from the observed changes in pH by a numerical solution to the equilibrium equations are in excellent agreement with the analytical values.
Improved apparatus for the differential measurement of pH: applications to the measurement of glucose / A. Mosca, G. Dossi, M. Luzzana, L. R. Bernardi, W. S. Friauf, R. L. Berger, H. P. Hopkins, V. Carey. - In: ANALYTICAL BIOCHEMISTRY. - ISSN 0003-2697. - 112:2(1981 Apr), pp. 287-94-294. [10.1016/0003-2697(81)90295-5]
Improved apparatus for the differential measurement of pH: applications to the measurement of glucose
A. MoscaPrimo
;
1981
Abstract
Two improved systems for the determination of the difference in pH between two solutions at the same temperature are described, both of which have a long-term stability of ±1 × 10-4 pH unit and a peak-to-peak noise level of 5 × 10-5 pH unit when operated in the differential mode. The cells are constructed of Delrin which has been found to be inert in biological fluids. These cells, with a volume of 1 ml, can be electrically connected to each other via a dialysis membrane and are thermostated during the duration of the pH measurements to ±0.01°C. In a second configuration, combination microelectrodes are inserted into each cell; thus the dialysis membrane is not necessary. To demonstrate the application of these systems to reactions of biological interest where pH changes occur, we investigated the hexokinase-catalyzed reaction between ATP and glucose in a phosphate buffer. The concentrations of glucose determined from the observed changes in pH by a numerical solution to the equilibrium equations are in excellent agreement with the analytical values.Pubblicazioni consigliate
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