If your industry lies in medicine, biology, food and beverage, agriculture, or quality control, you’ve likely come across pH meters in your line of work. These instruments are essential for maintaining appropriate safety and quality standards across multiple applications.
But if you’re not using your pH meter effectively, you could be taking inaccurate or unreliable results. To get the most out of your pH meter, it’s critical to understand how the tools work, choose the right type for your application, and calibrate the meter regularly for optimal accuracy.
How do pH meters work?
A pH meter’s purpose is to measure the acidity or alkalinity of a solution. They achieve this by measuring the solution’s hydrogen-ion concentration, which is expressed as pH on a scale from 0 to 14.
Most pH meters feature two main components, the meter itself (which can be digital or analogue) and up to two probes you’ll need to immerse in the solution to begin testing. As you insert the probes into the solution, you’ll create a complete electrical circuit.
The meter will then measure the voltage between the two probes or electrodes, convert the result into a pH value, and display it on the digital or analogue screen.
Types of pH meters
There are a few different types of pH meters available today. To achieve the best results, choose a pH meter that suits your application and your industry’s unique needs.
The main four types of pH meters are:
- Portable or handheld pH meters, which use Bluetooth technology, allowing the user to download the information to a PC, tablet, or mobile phone.
- Pocket testers, which are easily transportable, lightweight, and display results on a clear LCD screen. These meters are popular for researchers and students during fieldwork.
- Bench meters sit atop a counter or bench, making them great for laboratory use. These meters also often come with Bluetooth and PC connectivity features.
- Test kits use colour saturation to measure the weakness or strength of a chemical’s presence. Low saturation indicates a low concentration while deep saturation reflects a high concentration.
Calibrating your pH meter
Once you’ve chosen the right kind of meter, you’ll need to calibrate it for optimal accuracy. The calibration process is quite simple—all you’ll need is a buffer solution or two, distilled water, clean beakers, a cleaning solution, and the pH meter itself.
Now, here’s the process to follow:
- Make sure the pH probe is clean and free from damage or contamination.
- Flush the sensor using distilled water.
- Fill a clean beaker with your buffer solution and immerse the probe in the liquid.
- Leave the probe in the solution until the value stabilises. This should take one to two minutes.
- Once the value stabilises, press the ‘calibrate’ button on your pH meter to set the adjustment point or calibration value.
- For optimal accuracy, flush the sensor and calibrate again using a second buffer solution.
Effective pH meter use is easy
As long as you choose the right pH meter for your application and calibrate it regularly, you should have no trouble achieving accurate and reliable results every time.
