The use of electrolyte analyzer

Electrolyte analyzer principle of use Clicks: 50 Release time:2011-5-26

The principle of use of electrolyte analyzer, commonly used electrode structure:

Sodium Electrode Features: Sodium Electrode is a glass capillary electrode used to determine the concentration of sodium ions in liquid samples. The main structure:

Electrode cover: transparent plastic.

Measuring capillary: sodium-sensitive glass.

Electrode chamber: sealed, filled with sodium electrolyte.

Electrode core: Ag, Agcl

Potassium Electrode Features: The potassium electrode is a membrane electrode that also measures the concentration of potassium in the sample.

The main structure:

Electrode cover: transparent plastic.

Measuring capillary: potassium ion sensitive membrane.

Electrode chamber: sealed, filled with K fluid.

Electrode core: Ag/Agcl

Chlorine Electrode Characteristics: The chlorine electrode is also a membrane electrode that measures the Cl ion concentration in the sample.

The main structure:

Electrode cover: transparent plastic.

Measuring capillary: Cl ion sensitive membrane.

Electrode chamber: sealed and filled with Cl-liquid.

Electrode core: Ag/Agcl

Reference electrode characteristics: The reference electrode is a device that connects the sample to the signal ground.

The principle of use of the electrolyte analyzer, the main structure: The reference electrode consists of two parts: the reference electrode cover and the reference electrode core. The reference solution in the reference electrode sheath forms a salt bridge between the reference electrode core and the sample. At the start of each measurement, the reference solution is injected into the reference electrode sheath, and a small portion of the reference solution is made of glass. The capillary tube penetrates into the measuring chamber so that a salt bridge is formed between the sample and the reference electrode core, and the reference electrode core forms a loop between the electrical signal ground and the reference liquid.

Electrolyte analyzer principle, measurement process: ion selective electrode, the electrode contains a known ion concentration of the electrode solution, through the ion selective electrode membrane and the corresponding ion in the sample infiltration, so as to produce a membrane potential on both sides of the membrane, the sample ion When the concentration is not used, the magnitude of the generated potential signal is also different. By measuring the magnitude of the potential signal, the concentration of ions in the sample can be determined.

The difference in ion concentration between the liquid and the sample in the electrode causes the electrode membrane to generate an electrochemical potential. This potential can be taken out by the electrode and sent to the input of the amplifier. The other input of the amplifier is connected to the reference electrode and grounded. The voltage of the electrode can be further amplified. . The voltage difference is formed and determines the ion concentration of the sample under test.

3. Research Process Ion migration occurs in the aqueous layer of the ion selective electrode membrane matrix when the measured ion contact electrode in the electrode solution. There is a potential change in the charge of the migrating ions, which changes the potential between the membrane surfaces; a potential difference is generated between the measuring electrode and the reference electrode. The potential difference between the ideal ion-selective electrode and the ion to be measured in the solution should conform to the Nernst equation: E=E0 log10a(x)

E: measured potential E0: standard electrode potential (constant)

R: Gas constant T: Absolute temperature Z: Ion valence F: Faraday constant a(x): Activity of the ion Visible The measured electrode potential is proportional to the logarithm of the activity of the "X" ion when the activity coefficient is maintained At a constant level, the electrode potential is also proportional to the logarithm of the ion concentration (C), and the activity or concentration of the ions in the solution is determined.

At present, there are many manufacturers of sodium-potassium chloride ion electrode analyzers, but the used electrodes are basically the same. The sodium is mostly made of lithium aluminum silicate glass electrode membrane and has a longer life. The potassium electrodes are mostly made of phylloline membranes.

The main components of the ion selective electrode analyzer Na, K, Cl-electrode have a predetermined life, and need to be replaced regularly. Under normal circumstances, after many times of maintenance of the electrode, and ensure the smooth flow of the pipeline, the electrode can not pass through multiple calibration, you need to replace this electrode.

Observing these extremely damaged electrodes, it was found that the reason for the reported loss was that the electrode surface inside the electrode was lower than the silver needle surface. When measuring the sample, the measured potential difference can not be transmitted to the reference electrode through the silver needle to do the amplification and measurement in the next step. The principle of use of the electrolyte analyzer is used.