Hydrogen-pH-Electrode pHydrunio

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pH-Electrode pHydrunio – Hydrogen-pH-Electrode
Principle of Hydrogen-pH-Electrode pHydrunio
Hydrogen potential and pH value

pH-Electrode pHydrunio – Hydrogen-pH-Electrode

Now it’s on the market : the first hydrogen pH electrode made by Gaskatel: pHydrunio (Patent DE 10 2011 113 941). It combines a reversible hydrogen electrode as a measuring electrode in your solution with a hydrogen reference electrode in an inner electrolyte as a reference electrode. It comes activated. You just have fill in the inner electrolyte, f. e. buffer pH 7 and after 24 hour pHydrunio is ready. It is supplied for 12 months by an internal source with hydrogen gas. Then the hydrogen cells can be exchanged. Simultaneously, the hydrogen makes the inside of the shaft to a controlled leakrate of electrolyte through the diaphragm. It is made of plastic and therefore indestructible .

  • Fill in an inner electrolyte with well known pH Innenelektrolyten, wait 24 hours and than start your measurements
  • Runtime 12 month, then the hydrogen cells can be exchanged easily
  • indestructible because it’s made of plastic
  • controlled leakrate
  • for pH -2 bis pH 16
  • for use in concentrated fluoride media
  • Shaft diameter 12.7 mm, shaft length

Are you interested in our hydrogen pH electrode – then please contact us.

We offer our hydrogen pH electrode and service all over the world (USA, Asia, Africa, Australia, New Zealand, Europe).

 

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Principle of Hydrogen-pH-Electrode pHydrunio

The hydrogen electrode is the only electrode whose potential is directly determined by the hydrogen ion activity.

pH and hydrogen potential are directly linked

pH and hydrogen potential are directly linked

What could be better than to combine two hydrogen reference electrode to a combination electrode to provide a novel hydrogen – pH electrode. The miniaturization of the hydrogen electrode Hydroflex did exactly this possible. Two hydrogen electrode are combined to a pH electrode. The internal hydrogen electrode (1) is the reference electrode. It must be immersed in a buffer with known pH. A diaphragm is for the ionic connection with your test sample. The outer hydrogen electrode (2) is the actual measuring electrode. Between two hydrogen electrodes is tapped directly with a voltmeter the voltage. You can connect pHydrunio to commercial pH meter or to a simple multimeter, because unlike the conventional glass electrodes our Hydrogen pH electrode has a low resistance.

Principle of hydrogen pH electrode pHydrunio. Two hydrogen electrodes are combined to a pH electrode. The internal hydrogen electrode (1 is the Reference electrode. It must be immersed in a buffer with known pH. A diaphragm is the ionic connection to the test sample. The outer hydrogen electrode (2) is the measuring electrode. Between this two hydrogen electrodes is tapped directly with a voltmeter the voltage.

Principle of hydrogen pH electrode pHydrunio. Two hydrogen electrodes are combined to a pH electrode. The internal hydrogen electrode (1) is the Reference electrode. It must be immersed in a buffer with known pH. A diaphragm is the ionic connection to the test sample. The outer hydrogen electrode (2) is the measuring electrode. Between this two hydrogen electrodes is tapped directly with a voltmeter the voltage.

Sensitivity ( Nernst slope , slope) of the pH electrode pHydrunio

Sensitivity ( Nernst slope , slope) of the pH electrode pHydrunio

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Hydrogen potential and pH-Value

The hydrogen potential is directly dependent on the activity and concentrations of hydronium and thus the pH of the solution. The pH itself is defined as the negative logarithm of the hydrogen ion activity.
The activity is the product of concentration and activity coefficient. The latter can only be approximated in dilute solutions. Thus can be done in accordance with its definition only in good approximation, the measurement of pH. If two hydrogen electrodes, one of which in an acid proton concentration 1 mol/l (normal hydrogen electrode, NHE ) and the second in a solution of unknown concentration of protons (reversible hydrogen electrode, RHE ) is immersed, a salt bridge in contact with, so you have a concentration cell present or concentration cell.

Concentration cell of 2 hydrogen electrodes.

Concentration cell of 2 hydrogen electrodes fpr measuring pH-value.

Once you combine two half-cells in contact and closes the electric circuit, the potential of the spontaneously occurring reaction sets. Due to the higher concentration of protons in the left half cell – here hydrogen ions – are reduced to hydrogen. Here, the electrode electrons are withdrawn, and it has a more positive potential than the electrode in the right half-cell. In the left half cell so that reduction takes place. This cell corresponds to the cathode and is in the galvanic cell of the positive pole.In the right half-cell, hydrogen is oxidized to hydrogen ions. The electrode has a more negative potential than the left electrode (negative pole). In the right half-cell contains the oxidation, and it corresponds to the anode. The voluntary flow direction of the electron passes from the negative terminal to the positive pole, in this case – galvanic cell – from the anode to the cathode. So electrons flow here from right to left, so the more dilute the concentrated cell.
The potential is given by E = E(right) – E(left). The standard hydrogen electrode must be left cell of IUPAC.

Calculation of the potential of a proton concentration chain by convention.

Calculation of the potential of a proton concentration chain by convention.

The potential changes formally with a positive sign, depending on the proton concentration.
BUT: we have a logarithmic function of the proton concentration. For concentrations < 1 mol/l, therefore give negative potentials here for a 0.1 mol/l HCl arise -0059 V. Including the proton concentration in the pH in a way, the calculation of the potential created much easier.
E = – 0.059 pH (25°C)

Because E < 0 volts, the reaction is thus spontaneously from right to left as is to be expected due to the different concentrations.To measure in such a concentration cell also negative potentials, you must connect the standard hydrogen electrode to the negative pole (Com port). Further specifications for potential calculation are: E = E(cathode) – E(anode) = E(acceptor) – E(donor). However, positive potentials arising in the calculation then, depending on the pH.

Calculation of potential.

Calculation of potential.

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Are you interested in our hydrogen pH electrode – then please contact us.
We offer our hydrogen pH electrode and service all over the world (USA, Asia, Africa, Australia, New Zealand, Europe).

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