Use and maintenance of ion meter

Use and maintenance of ion meter

 

Core tip: the ion meter is used to measure the ion concentration in the solution by electrochemical analysis instrument. The meter of h+ is also an ion meter. We generally call it pH meter or acidity meter. Generally speaking, the ion meter refers to the electrochemical instrument for measuring other ions except h+

An electrochemical analytical instrument used to measure the concentration of ions in solution. Measuring H + also belongs to the ion meter, we generally call it pH meter or acidity meter, generally people refer to the ion meter is to measure other ions except H + electrochemical instrument。

 

According to the test principle of ion meter, the ion selective electrode has a selective response to a certain ion. When it contacts with the ion, the electrode surface potential changes. According to Nernst equation, the ion activity or concentration value of the measured sample is calculated. Therefore, the weak change of power supply can obviously affect the test results. Moreover, the power supply voltage is unstable, and repeated switching will directly damage the electrode, The aging rate of electrode is accelerated. Therefore, those who have the conditions should be equipped with on-line two-way cut-off power supply with stable voltage and anti-interference and power-off protection, so as to eliminate the voltage instability, noise interference and adverse effects caused by sudden power-off due to line overload and random switch。

 

The adhesion of protein to the electrode membrane can change the electrode membrane potential, resulting in error or calibration failure of the specimen detection results. It is necessary to clean and adjust the electrode of the ion meter in time to remove protein. The cleaning solution containing sodium hypochlorite can be used for removing protein. The adjusting solution containing NH4 and Hf2 has the effect of activation potential on Na, ++Cl and electrode. A better electrolyte analyzer has the function of automatic cleaning and adjustment. When the electrode is used for a long time and the protein dirt cannot be completely removed by automatic cleaning, the electrode can be taken off and soaked in the cleaning solution for a period of time, and the cleaning solution is injected through one electrode hole with a syringe or ear ball, and then rinsed repeatedly. Keep the instrument energized at all times to ensure that the electrode is wet. When the electrode must be turned off, the reagents can be inhaled by means of electrode test to fill the measuring chamber with reagents. In addition to careful maintenance of the electrode, the use of two electrodes of the same kind alternately (do not use dry, fill the inner liquid, storage for a period of time can enhance the sensitivity of the electrode film), can slow down the electrode aging. When calibration and measurement, the front door of the instrument should be closed to prevent external magnetic interference, which can lead to serious electrode drift or disorder can not be used。

 

The calibration, testing and washing of the ion-meter analyzer must have reagents involved, even in the standby state, there is still a small amount of reagents around the electrode, if the reagent has a problem, the chemical composition may cause damage to the electrode, and the accuracy of the electrode voltage value test results can not be guaranteed. In principle, reagents from the original manufacturer should be used. If non-original reagents are used, they should meet the requirements of the manufacturer. Reagents that cannot pass the calibration, electrode test voltage value is lower than the normal range and specimen test results are inaccurate should be firmly replaced。

 

Ion meter selective electrode is also called ion electrode. An electrochemical sensor that uses membrane potential to determine ion activity or concentration in a solution. The glass electrode for measuring the pH of solution, which was first studied by R. Kreamer in 1906 and then made by F.Harber et al in Germany, was the first ion selective electrode. By the end of 1960s, there were more than 20 kinds of ion selective electrode products. The ion selective electrode has the ability to convert the activity of a specific ion in solution to a certain potential, which is linearly related to the logarithm of the activity of a given ion in solution. Ion-selective electrode is a membrane electrode, and its core component is an induction membrane at the electrode tip. According to structure, it can be divided into solid film electrode, liquid film electrode and diaphragm electrode。