pH Meter simple and inexpensive

Ph meter is an electronic device used to measure the concentration of hydrogen ions in the solution. Hydrogen ion concentration is the value which decides the nature of any solution as acidic or alkaline. The term pH was coined by danish scientist S.P.N Sorenson in 1909 . He has abbreviated pH as " ponds hydro genii".

Fundamentally Ph Meter consists of a voltmeter attached to a ph-responsive electrode and a reference ph electrode which is of fixed ph value. pH- responsive electrode is generally made of glass while reference electrode is mercury-mercurous chloride electrode, however a silver-silver chloride electrode is also used as reference. As an ideal test condition we must ensure that only the pH value of pH responsive electrode is changing upon concentration while the pH value of reference electrode must be constant throughout the test process so as to generate an effective potential difference.

When both these electrodes are immersed in a solution they form a battery. Glass electrode generates a charge(potential difference) which is directly according to the concentration of hydrogen ions, means will be higher if the solution have rich hydrogen ion concentration. The voltmeter attached measures the potential difference thus generates due to glass electrode and reference electrode and the value thus obtained is the pH score for the solution which we can compare to standard pH chart and depending on where the pH score of solution lies, we say it acidic or alkaline. As per the standard set for pH value in the field of chemistry and biology, if the pH value is below 7 then the substance is called as of acidic nature while if the pH score exceeds 7 it is said to have basic or alkaline nature. More often if any solution have pH Controller value of exactly 7 then it is marked as neutral i.e. Neither acidic nor alkaline.

For precise working of pH meter it must be calibrated every time before use. If we are using pH meter in normal use than daily calibration is required. The need of calibration required because the glass electrode is not able to generate the same emf over a period of time continuously. So in order to avoid any tolerances in the result, calibration is a good practice. Depending upon the various factors each pH meter is calibrated on number of iterations called as point, which is generally termed as 1st point calibration, 2nd point calibration and 3rd point calibration. Both the electrodes i.e. Glass electrode and reference electrode have a definite set of maintenance instructions which must be followed each time after completion of test and should be preserved carefully.

Types:

pH meter type ranges from simple and inexpensive pen like meter to some more advanced laboratory installed pH Meter equipped with various input interfaces and display indications. Some more advanced meters provides sensitivity towards temperature when slight change in temperature can cause considerable variation in our measurement.

Below are the set of precautions we must follow to get most accurate measurement results:

·         Use quality equipments

·         Maintenance of electrodes

·         Proper calibration of pH meter

·         Follow proper test procedure