:琼脂（Agar），又名琼胶、菜燕、冻粉，是一类从石花菜及其它红藻类（Rhodophyceae）植物提取出来的藻胶（phycocottoid），在我国及日本已有三百多年（1658年）的历史。琼脂糖Agarose，缩写为AG，是琼脂中不带电荷的中性组成成份，也译为琼胶素或琼胶糖。琼胶糖化学结构由β-D-吡喃半乳糖(1-4)连接3,6-脱水α-L-吡喃半乳糖基单位构成.
用途:琼脂、琼脂糖因为有特殊的胶凝性质，尤其有显著的稳固性、滞度和滞后性，并且易吸收水分，有特殊的稳定效应；已经广泛使用于食用、医药、化工、纺织、国防等领域，据不完全统计，琼脂、琼脂糖的用途已有1000多种，被国际上称为“新奇的东亚产品”。在食品工业中可用于生产：水晶软糖、定型软糖、水产品、肉类罐头、果汁饮料、果肉饮料、米酒饮料、乳品饮料、精品、乳品蛋糕。
近年来由于其良好的生物相容性又广泛用于生物分离介质的生产.
Biowest相关资料如下:
最权威的西班牙琼脂糖（Biowest Agarose）是一种电泳级别纯度很高的产品，作为著名的琼脂糖品牌，具有极佳的产品性价比，在同行中有着非常高的知名度，在同类产品中占据着最高的市场份额，西班牙琼脂糖（Biowest Agarose）不仅适用于蛋白电泳也可以用于其它核酸分析电泳。
技术参数：Agarose Low EEO
Gel Strength (1.0%) (g/cm2)………………≥750
Gelling Range (1.5%) (℃)………………36 - 39
Melting Range (℃)………………………87 - 89
EEO (-mr)……………………………………≤0.15
Sulfate (%)………………………………≤0.15
DNase……………………………………None Detected
RNase……………………………………None Detected
Protease………………………………None Detected

Introduction:
Routine use agarose is ideal for everyday analysis of nucleic acids by gel electrophoresis or blotting (Northern or Southern) and is also suitable for protein applications such as Ouchterlony and radial immunodiffusion (RID).
Analysis Note :
Sulfate content - used as an indicator of purity, since sulfate is the major ionic group present.
Gel strength- the force that must be applied to a gel to cause it to fracture.
Gel point- the temperature at which an aqueous agarose solution forms a gel as it cools. Agarose solutions exhibit hysteresis in the liquid-to-gel transition - that is, their gel point is not the same as their melting temperature. 
Electroendosmosis (EEO) - a movement of liquid through the gel. Anionic groups in an agarose gel are affixed to the matrix and cannot move, but dissociable counter cations can migrate toward the cathode in the matrix, giving rise to EEO. Since electrophoretic movement of biopolymers is usually toward the anode, EEO can disrupt separations because of internal convection.

Preparation of Agarose Gels for DNA separations:
Weigh out the desired amount of agarose and place in an Erlenmeyer flask with a measured amount of electrophoresis buffer, e.g. for an 0.8% gel, add 0.8 gm of agarose and 100ml of TBE Buffer (1X), to a 200 ml flask. The larger flask insures against the agarose boiling over. Dissolve the agarose in a boiling water bath or in a revolving-plate microwave oven. All the grains of agarose should be dissolved and the solution clear. Cool the solution to 60°C (70°C for concentrations 2% or above) and pour immediately. Allow the gel to set for one-half hour before using. Make sure to use the same electrophoresis buffer in the gel as for the running buffer.