Molecular Biology Reagents and Biological Buffers

We offer sterile formulations of common biological buffers such as PBS, DPBS, Tris, HEPES, and SSC, as well as custom formulations.

Products that are “Molecular Biology Grade” are quality tested for contaminants such as DNase, RNase, and proteinase. These reagents are typically used in applications like PCR, cloning, electrophoresis, Western Blotting, and DNA, RNA, or protein experiments.

Most of our Molecular Biology reagents will have a shelf life of 24 to 36 months depending on the product formulation. You can find the shelf life for each product on the product web page. The expiration date for the product lot is printed on the product label.

One of the most important factors when selecting a buffer is the pH range. The buffer selected should also be compatible with the protocol and potential interactions with sample components.

Other critical factors to evaluate are the pKa of the buffer (which should be close to the target pH), water solubility, minimal interference with biological molecules, salt concentration, and potential interactions with other components in your reaction.

Tris buffers are typically used in molecular biology experiments involving nucleic acids and proteins. PBS buffers are typically used in cell biology for washing cells and maintaining physiological pH.

QBI Molecular Biology ready-to-use buffers are prepared according to standard known and published formulations. Custom Molecular Biology buffers are manufactured to formulations specifically requested by our clients.

Yes, we provide custom buffer formulation services, including concentration, pH adjustment, and packaging size. Let us know what you need by completing our Customer Formulation Form.

All our TE buffer products –  TE Buffer, pH 8.0, TE Buffer, pH 7.5, or TE Buffer, pH 7.4  – contain 10mM Tris (T) and 1mM EDTA (E).

In addition, we provide a Low EDTA TE (1X), pH 8.0 buffer, containing 0.1mM EDTA rather than 1mm EDTA.

See the table below.

w/v: weight/volume
v/v: volume/volume

QBI products containing xylene cyanol and/or bromophenol blue are:

• RNA Gel Loading Buffer – xylene cyanol and bromophenol blue
• RNA Gel Loading Soluton (10X) – xylene cyanol and bromophenol blue
• DNA Gell Loading Solution (5X)  – xylene cyanol and bromophenol blue
• Modified SDS Protein Gel Loading Solution – bromophenol blue
• SDS Protein Gel Loading Solution (2X) – bromophenol blue

The dyes migrate as follows:

• In 1% agarose TAE buffer, Xylene cyanole-4160 bp, bromophenol blue-370 bp
• In 1% agarose TBE buffer, Xylene cyanole-3030 bp, bromophenol blue-220 bp

The formulation is 0.2M MOPS, 0.08M Sodium acetate-3H2O, 0.01M Disodium EDTA--2H2O, pH adjusted to 7.0.

Formamide, an organic denaturant, is commonly used in nucleic acid applications such as sequencing. It is well known that formamide, even at very low temperatures (e.g., –20 ° C), will break down into formic acid and ammonia. Both by-products are capable of degrading RNA and DNA. If the use of formamide is required for your application, it is prudent to use freshly deionized formamide before adding it to our DNA Gel Loading Solution and/or to our RNA Gel Loading Solution.