Biochemicals - Buffers, Dyes & Probes - Background

Featured Buffer, Dye, and Probe Products

HEPES, Free Acid, ULTROL^® Grade – has the ability to maintain physiological pH despite changes in carbon dioxide concentration is superior when compared to other bicarbonate buffers also used in cell culture.

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DAPI, Dihydrochloride -

A cell-permeable DNA-binding dye, DAPI binds preferentially to DNA rich in adenine and thymine. Useful for microscopic detection of nuclei and nuclear DNA in normal and apoptotic cells. Can also be used to detect mycoplasma.

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Buffers Background

Below are highlights and summaries from the Essential Biochemicals for Research, which is a technical resource and product guide for scientists for the preparation and use of biochemicals such as antibiotics, buffers, detergents, dyes, stains, and substrates, which are indispensable for any life science research laboratory. To view the full content, please download or request a print copy of this resource.

Criteria for Suitable Biological Buffers

Biological buffers should meet the following general criteria:

Their pKa should be between 6.0 and 8.0.
They should exhibit high water solubility and minimal solubility in organic solvents.
They should not permeate cell membranes.
They should not exhibit any toxicity towards cells.
They should not interfere with any biological process.
The salt effect should be minimal; however, salts can be added as required.
Ionic composition of the medium and temperature should have minimal effect on buffering capacity.
Buffers should be stable and resistant to enzymatic degradation.
Buffers should not absorb either in the visible or in the UV region.

Preparation of Some Common Buffers for Use in Biological Systems

The information provided in Quick reference guides section of the Technical Resource Book provides common guidelines for preparation of common buffer. It is intended only as a general guideline. We strongly recommend the use of a sensitive pH meter with appropriate temperature setting for final pH adjustment. Addition of other chemicals, after adjusting the pH, may change the final pH value to some extent.

Some Useful Tips for pH Measurements
A pH meter may require several minutes to warm up.

Before you begin make sure the electrode is well rinsed with deionized water and wiped off with a clean absorbent paper.
Always rinse and wipe the electrode when switching from one solution to another.
Calibrate your pH meter by using at least two standard buffer solutions.
Do not allow the electrode to touch the sides or bottom of your container.
Do not stir the solution while taking the reading.