How to calibrate your pH electrode
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- Опубліковано 15 лип 2024
- In this video, we show you how to calibrate a pH electrode on a 913 pH/DO Meter or 914 pH/Conductometer. Calibration of your pH electrodes is essential for accurate pH measurements.
You will learn:
- how often you should calibrate your electrode,
- which material you need for the calibration,
- how to set the parameters for the calibration on the meter,
- how many buffers you should use,
- and why you need to measure the temperature during calibration.
Find more tips and tricks for pH measurements on our blog:
FAQ: All about pH calibration: www.metrohm.com/en/discover/b...
Avoiding the most common mistakes in pH measurement: www.metrohm.com/en/discover/b...
0:00 Introduction
0:27 Calibration frequency
1:07 Material needed for calibration
1:45 Preparations for the calibration
2:22 Settings on the meter
2:38 How many buffers should you use
2:55 Selection of buffer type
3:03 Start calibration
3:36: Effect of temperature on calibration
3:55 Continuation of calibration
5:08 After the calibration - Наука та технологія
Muy buen video y lo explica muy bien.
Thank you for running over the basics of pH calibration and a reminder to calibrate more often to ensure consistent sample accuracy!
Glad it was helpful!
@@MetrohmTV Is it still advisable to use pH 9 buffer for calibration bracketing samples with expected higher pH values, even though alkaline buffers have a high CO2 uptake?
For precise pH measurement results, we always recommend a multi-point calibration. The pH of the sample should always be within the pH range of the buffers that are used for calibration to minimize errors. So, if you are expecting higher pH values (e.g., pH 8) the use of pH buffer 9 is advisable.
To avoid a carbon dioxide uptake of buffers with higher pH values, always use fresh buffer solutions. Our buffer solutions in single use sachets are quite suitable for this.
If you have more questions on pH measurement and calibration please have a look at our current monograph “pH-measurement - everything from A-Z including best practices and examples”:
www.metrohm.com/en/products/8/1085/81085081.html
Thanks for the detailed calibration video.
You're welcome!
Nice video...
Thanks!
thank you for the detailed explanation
Addition of NaOH or HCl to adjust the PH of a solution does not affect the initial concentration of a solution?
Hi gidissadeksissa2219
Do you mean the initial concentration of an analyte? The initial concentration of an analyte is not affected if the analyte is sodium, hydroxide, hydronium, or chloride. Does this answer your question, or did we misunderstand it?
Best regards
Metrohm International Headquarters
Nice explanation 👌
Thank you 🙂
Is it necessary to maintain the buffer temperature externally at exact 25 degree celcious during calibration and sample pH measurment as well
Since temperature has an impact on your pH measurement (Nernst equation), calibration and pH measurement should be performed at the same temperature, e.g., at 25 °C. For further information please read our blog post “How temperature influences the pH value”:
www.metrohm.com/en/discover/blog/2023/how-temperature-influences-the-ph-value.html
Great video 😊! Why only 4,7,9 buffers used for calibration!
What is the maximum limit can dip the ph electrode or need to only dip the end of the electrode
Hi Samuel
Thank you for your comment. You always have to calibrate with buffers which lie within your measuring range. With buffers pH 4, 7, and 9, you’re already covering quite a broad pH range. Should you need to cover an even broader range, you can use pH buffers from other manufacturers.
As for the electrode: The electrode has to be dipped in in such a way that the diaphragm is fully covered by your measuring solution. I.e., the glass membrane and diaphragm have to be immersed but the electrolyte filling hole has to stay above the sample.
Best regards
Michel, Metrohm International Headquarters
@@MetrohmTV 😀 thanks for your reply 😊
Hello, I have a new HACH PHC101 electrode, but I can not calibrate, it says (standard not recognized. Rinse the electrode and repeat). Can you help me and tell me the reason?
Hi
Thank you for your comment.
Could you please check if another electrode can be calibrated? This way we would know if the problem lies with the instrument or the sensor.
In general, if you require instrument support, please contact your local Metrohm organization or exclusive distributor.
BR
Michel, Metrohm International Headquarters
Why do I have to calibrate more often when performed at high temperatures? If I do it at 28 degrees Celsius, is calibration necessary every day?
We would recommend calibrating the sensor daily and at the temperature of the samples for exact results. It depends a bit on the accuracy that is required.
I always use three buffer : pH 4 - 7 - 9
That's exactly the right way to do it!😊
Why the calibrate during first buffer taking much, sometimes wait around 45 minute still cannot proceed to next buffer
Hi
Thank you for your comment. Typically, a buffer measurement should not take more than a few seconds or a few minutes at most. A measuring time of 45 minutes is a clear indicator that something is not right, the most obvious candidate being a defective electrode. Please check whether your electrode needs to be replaced or contact your local Metrohm organization if you need technical support:
www.metrohm.com/en.html#country-selection
Best regards
Metrohm International Headquarters
What is ideal slope value after pH calibration.
The electrode slope is given by the Nernst equation and is 0.059 V per pH 1 at 25 °C. These are ideal values from which new Metrohm pH electrodes only differ slightly. The electrode zero point is ± 0.015 V. But please be aware that the electrode zero point and the electrode slope may change as a result of the aging of the glass membrane or changes (e.g., contamination) on the diaphragm.
For more information on this topic, please read our blog “FAQ: All about pH calibration”:
www.metrohm.com/en/discover/blog/20-21/faq--all-about-ph-calibration.html
And our our application bulletin AB-188 “pH measurement technique”:
www.metrohm.com/en/applications/ab-application-bulletins/ab-188.html
Where do we store the buffer solution if we are not making fresh everyday
Hi
Buffer sachets are for single use only. Metrohm buffers in the bottle last up to 3 months after opening and are easy to store on shelves. After a calibration, the buffer should be discarded and should not be reused.
You can find more information in this blog post:
www.metrohm.com/en/discover/blog/20-21/faq--all-about-ph-calibration.html
What is the problem when the slope is Less than 97%?
And pH(0) is higger than 7.10?
Hi Erick
There could be various reasons for this. You can find additional information on this topic in our Application Bulletin AB-188:
www.metrohm.com/en/applications/ab-application-bulletins/ab-188.html
If you need to troubleshoot your instrument or sensor, please get in touch with your local Metrohm subsidiary or exclusive distributor:
www.metrohm.com/en.html#country-selection
BR
Michel, Metrohm International Headquarters