0.5ml ultra-clear microcentrifuge tubes, PP, DNase/RNase free, Assorted colors, 1000/pk.
Axygen clear microcentrifuge tubes are engineered to close with a "snap" and stay closed during boiling and centrifugation. They have been tested to 55 psi and are ready for autoclaving at 121°C for 15 minutes. The tubes are exceptionally clear with frosted caps for labeling, a 0.28mm piercing port, and can be used in any centrifuge up to 20,000 x g.
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配制分三步: 1) 1 M Tris-HCl (pH 8.0) 50 ml的配制:称取Tris碱6.06 g,加超纯水40 ml溶解,滴加浓HCl约2.1 ml调pH至8.0,定容至50 ml。
电泳缓冲液的另一个作用是使溶液具有一定的导电性,以利于DNA分子的迁移,例如,一般电泳缓冲液中应含有0.01-0.04mol/L的Na+离子,Na+离子的浓度太低时电泳速度变慢;太高时就会造成过大的电流使胶发热甚至熔化。
电泳缓冲液还有一个组分是EDTA,加入浓度为1-2mmol/L,目的是螯合Mg2+ 等离子,防止电泳时激活 DNA酶,此外还可防止Mg2+离子与核酸生成沉淀。

