Orion Star™ A221 Portable pH Meter

At Thermo Fisher Scientific, we stand behind the quality and reliability of our instruments. That's why we offer a minimum two-year (2) warranty on all Orion benchtop and portable pH meters. Obtain peace of mind knowing that your investment is protected. Should any issues arise within the warranty period, our team of experts is committed to providing you with prompt and efficient service. Be sure to check instrument specifications to confirm the warranty coverage period.

Calibration is an important step to obtaining accurate results on your Orion benchtop or portable pH meter. Before beginning the calibration process, ensure that you are utilizing freshly poured, non-expired calibration buffers to help ensure accurate results. Follow the steps below to calibrate your pH meter.

• Prepare the calibration solutions: Obtain at least two pH reference solutions with known pH values. Ideally, use one solution close to the expected pH of your sample, and another solution at a different pH value. Ensure that the solutions are fresh and have not expired.
• Clean the electrode: Rinse the electrode with distilled or deionized water to remove any debris or contaminants. If necessary, gently wipe the electrode with a soft cloth or tissue.
• Turn on the pH meter: Power on the pH meter and allow it to warm up, if needed.
• Immerse the electrode: Immerse the electrode into a beaker containing the first calibration solution. Ensure that the electrode is fully submerged and that it is not touching the sides or bottom of the beaker.
• Allow stabilization: Allow the pH reading to stabilize. This may take a few moments, depending on the specific meter and solution being used. The reading should become steady and remain constant.
• Adjust the pH value: Using the calibration controls on the pH meter, adjust the reading to match the known pH value of the calibration solution. Reference the user manual for specific guidance on adjusting the pH.
• Rinse the electrode: After calibration, rinse the electrode with distilled or deionized water to remove any residual calibration solution.
• Repeat calibration: Repeat the calibration steps with the second calibration solution, following the same process as before.
• Verify accuracy: After calibration, it is recommended to check the pH meter's accuracy by measuring a pH solution of known value. This can help ensure the reliability of your measurements.

To learn more about pH meter calibration, download our technical note: Understanding Calibration of Laboratory pH Systems. See a live calibration by watching our video: Understanding Calibration of Laboratory pH Systems.

Before beginning an analysis on your Orion benchtop or portable pH meter, assemble your materials. You will need a pH electrode suitable for your application, calibration buffer solutions, and a test sample. Follow the steps below to obtain your pH analysis.

• Calibrate the pH meter: Start by calibrating your pH meter using the calibration buffer solutions. Typically, you will need pH 4, pH 7, and pH 10. Be sure to reference the user manual for instructions on how to properly calibrate your pH meter.
• Prepare your sample: Ensure that your sample is at the desired temperature (most frequently room temperature). If necessary, filter the sample to remove any particles or impurities that could impact the pH reading.
• Immerse the electrode: Dip the pH electrode into the sample. Avoid touching the sides or bottom of the container to prevent inaccurate readings.
• Allow for stabilization: Give the pH meter some time to stabilize and reach a steady reading. This may take a few seconds to a minute depending on your meter and the characteristics of the sample.
• Record the pH value: Once the pH meter stabilizes, record the pH value displayed on the meter. If applicable, also record the temperature value.
• Rinse the electrode: After each measurement, rinse the electrode with distilled or deionized water to remove any residue or contaminants. This helps ensure accurate subsequent readings.
• Repeat (if necessary): If you need to analyze multiple samples, repeat the process with each sample, recalibrating the pH meter if required.

To learn more about how to perform a pH analysis, watch our video:Measuring Drinking Water Using the Orion Versa Star Pro Bench Meter

When choosing an Orion pH electrode for your application there are many factors to consider. Sample type, container dimensions, accuracy/ precision requirements, junction design, durability, maintenance, and meter compatibility are all key features to evaluate.
To learn more about how to choose the right electrode for your application, watch our videos: How to Choose the Right pH Electrode and Understanding Your Sample to Select the Right pH Electrode

To perform an analysis using Orion benchtop and portable pH meters, you will need the following supplies: pH electrode (or micro electrode for small sample volumes/ containers), calibration buffer solutions, distilled or deionized water, sample containers, stirrer probe (optional), and electrode cleaning solution(s) (s). For your convenience, our all-in-one pH buffer kits can be purchased, which include pH buffers (4.01 pH, 7.00 pH, and 10.01 pH), electrode cleaning solution, and electrode and storage solution.