OD 260/280 is good, but the concentration and OD 260/230 is lower than previous samples. Concentrations ranged from an average of 190 ng / μl to 80-90 and OD 260/230 from 1.9 to below 1 (for example 0.83-0.33 0.44).

Also in the post-proteinase K phase and incubation at 37 ° C for 18-20 hours and the addition of sodium chloride, after centrifugation (14,000 RPM - 10 minutes), the proteins do not precipitate well, which causes the liquid to Do not separate the surface containing the DNA well.