10 Digital pH Meter Manufacturers in 2023
This section provides an overview for digital ph meters as well as their applications and principles. Also, please take a look at the list of 10 digital ph meter manufacturers and their company rankings.
Table of Contents
What Is a Digital pH Meter?
A digital pH meter is a machine that measures pH.
The electrode of the device is placed directly into the sample for measurement.
This device is used in a variety of fields and for a variety of purposes because it is easy to handle and affordable.
Most digital pH meters use the glass electrode method of measurement.
Other pH measurement methods include the use of indicator such as litmus paper, the hydrogen electrode method, the quinhydrone electrode method, and the antimony electrode method, but the glass electrode method is safer, more accurate, and more reproducible than other measurement methods.
Uses of Digital pH Meters
pH is one of the indicators that represent the environment of water bodies such as rivers, lakes, and marshes, and in chemical analysis, it is one of the indicators that affect sample pretreatment and analysis conditions.
In chemical analysis, it is one of the indicators that affect sample pretreatment and analysis conditions. pH also affects the progress of chemical reactions, so it is sometimes controlled at manufacturing sites.
Since pH must be measured accurately and easily in these various fields, digital pH meters are used in a variety of locations.
pH meters have different electrode dropouts depending on the application, and can be divided into porous (for general aqueous solutions) and sleeve (for viscous samples or samples containing a high percentage of non-aqueous soluble substances) types. (used for viscous samples or samples with a high content of non-aqueous soluble substances). The most appropriate pH meter should be selected based on the characteristics of the sample and container.
Principle of Digital pH Meters
pH is an indicator of hydrogen ion concentration in a liquid.
The glass electrode method is described here as a typical example of a pH measurement method. This method uses two electrodes (a glass electrode and a reference electrode). When a liquid of different pH is present in the two areas separated by the glass films of the electrodes, an electromotive force corresponding to the difference is generated. The pH is calculated by measuring the potential of the glass and reference electrodes with the instrument itself.
The pH meter must be calibrated before use. pH standard solutions are generally calibrated using pH 7 as the zero point and pH 4 and pH 9 as the three-point calibration, but the pH standard solution used for calibration may be changed depending on the pH of the sample. The slope of the calibration curve is affected by temperature.
pH measurement itself is simple, but it is important to keep the temperature of the pH standard solution and the sample as close as possible, to maintain the electrode properly, and to immerse the electrode's drop firmly in the sample. Although the pH measurement itself is simple, it is advisable to have a procedure for the key points of the measurement and maintenance method.
Calibration of Digital pH Meters
Calibrating a PH meter means correctly adjusting the zero and span points (sensitivity) of the PH meter using a pH standard solution. Since there are operations specific to the digital PH meters used, the instructions provided with the meter should be given priority when actually calibrating the meter.
Calibration can be performed in one-point calibration using one type of pH standard solution, two-point calibration using two types, or three-point calibration using three types, but two-point calibration is often used to calibrate PH meters.
One-point calibration is a simplified calibration. For more rigorous calibration, three-point calibration is used.
The actual value of "EMF per pH" at a glass electrode is affected by contamination of the glass film and "alkaline error" and "acid error" (errors in strong alkalinity and strong acidity, respectively). Therefore, the actual value is generally lower than the theoretical value (59.16mV at 25°C). The "pH7 EMF" also deviates from the theoretical value (0 mV).
By performing pre-measurement and periodic calibration, highly accurate pH measurement can be achieved.
The general procedure for two-point calibration is described below:
- Prepare two standard solutions: pure water for cleaning the electrode and the expected pH value of the solution to be measured between them. For more accurate calibration, heat or cool the standard solutions to a temperature close to that of the solution to be measured and keep the temperature constant.
- Wash the detection unit at least three times with deionized water and wipe off the water with filter paper or Kimwipes, being careful not to rub it hard.
- Take neutral phosphate standard solution in a beaker, immerse the detection unit, adjust it to the value of the pH standard solution relative to the temperature, and calibrate it (zero-point compensation).
- Remove the detector from the pH standard solution, wash it at least three times with pure water, and wipe off the water with filter paper.
- If the sample to be measured is expected to be less than pH 7 (acidic), take a beaker of phthalate standard solution or oxalate standard solution, immerse the detection unit, adjust it to the value of the pH standard solution relative to the temperature, and calibrate.
- If the sample is expected to have a pH of 7 or higher (alkaline), calibrate in the same manner using a borate or carbonate standard solution.
These operations are span point correction.
Repeat the zero point correction to span point correction until the indicated value of pH agrees within ±0.05 of the pH against the temperature of the pH standard solution.
Calibration Solution for Digital pH Meters
The types, quality, and composition of pH standard solutions are as follows:
- Oxalate pH Standard Solution is 0.05 mol/kg potassium trioxalate trihydrogen dioxalate solution with a pH of 1.68 at 25°C.
- Phthalate pH standard solution is 0.05mol/kg potassium hydrogen phthalate aqueous solution, pH 4.01 at 25℃.
- Borate pH standard solution is 0.01mol/kg sodium tetraborate solution, pH 9.18 at 25℃.
- The pH standard for carbonate is 0.025 mol/kg sodium bicarbonate and 0.025 mol/kg sodium carbonate solution, pH 10.02.
- The neutral phosphate standard solution is 0.025 mol/kg potassium hydrogen phosphate and 0.025 mol/kg disodium hydrogen phosphate solution, pH 6.86 at 25°C.
List of 10 Digital pH Meter Manufacturers
*Including some distributors, etc.
Sort by Features
- Default
- Company Size: largest first
- Year Founded: oldest first
- Year Founded: earliest first
Sort by Area
- Germany
- India
- United States of America
-
-
-
-
-
-
-
-
-
-
-
Omegasonics
Digital pH Tester
-
-
-
-
-
Turtle Tough Pty Ltd.
Digital pH Meters
-
-
-
-
-
Apera Instruments, LLC
Digital pH Meters
-
-
-
-
-
Milwaukee Instruments, Inc.
Digital pH Meters
-
-
-
-
-
Hanna Instruments, Inc.
Digital pH Meters
-
-
-
-
-
Devar Inc
Digital pH Meters
-
-
Digital pH Meter Manufacturer Ranking
*Including some distributors, etc.Number of Employees
- Mettler-Toledo: 16,200
Newly Established Company
- Mettler-Toledo: 1945 (78 years ago)
- Triplett Test Equipment & Tools.: 1904 (119 years ago)
Company with a History
- Triplett Test Equipment & Tools.: 1904 (119 years ago)
- Mettler-Toledo: 1945 (78 years ago)
Related Products
Search from All Categories
This is the version of our website addressed to speakers of English in Canada. If you are a resident of another country, please select the appropriate version of Metoree for your country in the drop-down menu.