为什么引物的OD260/OD280小于1.5？
需要指出的是OD260/OD280的比值不能用来衡量引物的纯度。OD260/OD280的比值过低一般是由于引物中C/T的含量比较高所致。下表是一个20base同聚体引物的OD260/OD280的比值，清楚表明OD260/OD280的比值与引物的碱基组成密切相关。
A260/280 ratios of Crude 20-mer Oligos of Differing Base Compositions | |
Base Composition | A260/280 |
5-AAAAAAAAAAAAAAAAAAAA-3 | 2.50 |
5-GGGGGGGGGGGGGGGGGGGG-3 | 1.85 |
5-CCCCCCCCCCCCCCCCCCCC-3 | 1.15 |
5-TTTTTTTTTTTTTTTTTTTT-3 | 1.14 |
5-AAAAAGGGGGTTTTTCCCCC-3 | 1.66 |
推荐
