Agarose; Agarose B Low Eeo CAS: 9012-36-6

1. Basic information of REGULAR AGAROSE:

CAS#: 9012-36-6

Molecular formula: C12H18O9

Molecular weight: 306.26

Appearance: white powder

Characteristics: Glue strength (1.0%) (g/cm2): >1200

Storage conditions: dry and store at room temperature

Alias: Sepharose

Solubility: insoluble in cold water, soluble in boiling water, slowly soluble in hot water;

2. In the biological experiment, after adding agarose to the sample, the analysis of the reason why it does not solidify at room temperature:

1. The pH value of the sample is too low, partial acidity, hydrolysis, and agarose cannot coagulate when the pH value is less than 4.

2. The quality of the added agarose is not enough, so increase the dosage. Stirring is not uniform, and the solidification is not uniform if it is not fully shaken before pouring.

3. The sterilization temperature is too high and the heating time is too long. The pH changes or destroys the degree of solidification of agarose.

4. The sample will not solidify without heating and dissolving sufficiently.

Third, the difference and classification of agar powder, agarose, and low melting point agarose in biological experiments:

Agar powder is composed of agarose (agarose) and agar pectin (agaropectin). Agarose is a linear polymer. The basic structure is 1,3-linked β-D-galactofuranose and 1,4-linked 3,6-anhydro α-L-galactofuranose. Agar pectin is a heterogeneous mixture composed of many smaller molecules. Their structure is similar, but with sulfate and carboxyl components, the gelling ability is poor. Simply put, remove the agar pectin in the agar, and the remaining part is the agar in the industry. The color of agar varies from white to slightly yellow. It has a gum texture, no odor or a slight characteristic odor, and the agar is insoluble. In cold water, it is soluble in boiling water and slowly soluble in hot water.

Agarose is generally heated to above 90°C to dissolve in water, and a good semi-solid gel is formed when the temperature drops to 35-40°C. This is the main feature and basis for its multiple uses. The performance of agarose gel is usually expressed by gel strength. The higher the strength, the better the gel performance. The strength of better quality agarose is usually above 1200 g/cm2 (1% gel concentration). The gelation of agarose is caused by the existence of hydrogen bonds. Any factor that can destroy the hydrogen bonds can cause the destruction of the gelation. Agarose is hydrophilic and has almost no charged groups. It rarely causes denaturation and adsorption to sensitive biological macromolecules. It is an ideal inert carrier. In the process of agarose preparation, it is necessary to remove the agar pectin as much as possible, otherwise there may be traces of sulfate and pyruvate in the agarose instead of ionizing groups, which will cause electroendosmosis (EEO), which will cause the movement of particles influences. Agarose with better quality has a lower sulfate content, usually less than 0.2%, and electro-endosmosis is relatively small, usually less than 0.13.

Gel strength expression method:
Specifications Gel strength (1.5% concentration solution, 20 degrees Celsius, individual grams per square centimeter)
Low strength 150-400
Medium strength 401-800
High strength 801-1200
Super high strength greater than 1200