What are the pros and cons of using liquid pH buffer compared to powder pillows?

Document ID

Document ID TE7403

Published Date

Published Date 17/04/2019
Question
What are the pros and cons of using liquid pH buffer compared to powder pillows?
Summary
Comparing liquid and powdered pH buffer.
Answer
Most customers prefer to use the liquid buffer because of the time saving aspect since the liquid buffer can simply be poured into a beaker and used.The buffer powder pillows must be combined with water, so it is necessary to measure the 50 mL of deionized (DI) water and mix the buffer powder pillow before it can be used. The other benefit of using liquid buffer is that any volume can be used. The powder pillows should be mixed with 50 mL DI water, but if smaller beakers are used its possible to use a smaller volume of the liquid buffer per calibration. This leads to less waste and potential cost savings. However there are some benefits of using the powder pillows. Since the buffer powder pillows are individually sealed the expiration date on the packaging is always correct which is not true for liquid pH buffers (see also What is the shelf life for liquid pH buffers?). Also the pH 10 buffer shelf life is doubled for powdered buffer compared to the shelf life of an unopened bottle of liquid buffer (pH 4 and 7 are the same for either powdered or liquid buffer). There may also be a small cost savings per mL of buffer after being mixed.
There are no differences in probe performance calibrating with liquid or powdered buffer. In terms of repeatability and accuracy they are identical.