DNA stuck in the gel well

[rchmelo]

The PCR product that I am trying to visualize is 320bp. After PCR, the reaction is loaded onto a 1.5% agarose gel and run at 110 volts for 1.5 hours. No product is observed except for a blob in the well. This is observed when using Phire polymerase. When the same primer set is used with AmpliTaq Gold or Promega Master Mix, this problem is NOT observed. I have talked to Finnzymes(ThermoFisher) and no solution yet. It has been over 4 weeks with this problem. Have tried all combinations of magnesium, primer and template concentration, and even proteinase K treatment of the PCR. Still no luck.

I have read the posts concerning this issue and nothing has worked to date. Any suggestions?

[r.rosati]

Topic split from DNA stuck in the gel well for clarity