Why does my purified DNA/RNA sometimes have a 260/280 or 260/230 ratio of more than 2? Does that mean the purity is poor?
FAQ ID -3132

 

High 260/280 and 260/230 ratios suggest that there is a strong absorption of light at 260nm, which is nucleic acid and there is minimal absorption occurring at 280nm and 230nm, which are protein and organic compound, respectively. The high ratio sometimes could be due to addition of carrier RNA to the purification procedure, which increases the nucleic acid yield and therefore the absorption at 260nm.