Potential problems include:
- Loading too much DNA. Do not load more than the recommended amount.
- Samples with a high salt concentration. Samples containing > 50 mM NaCl, 100 mM KCl, 10 mM acetate ions, or 10 mM EDTA will cause loss of resolution.
- Samples may have been diluted in TAE instead of TE or water.
- Samples may have been pre-run; pre-running is not recommended for any of our E-Gel agarose gels.
- Sample was not properly loaded or had a very low volume of sample loaded. Load the recommended sample volume based on the gel type and loading method. For proper band separation, we recommend keeping sample volumes uniform.
- Bubbles may have been introduced while loading the samples. Bubbles will cause band distortion. Load deionized water or TE into any empty wells, and avoid introducing bubbles.
- A longer electrophoresis run time was used. Do not run the gel longer than the recommended time for each gel type. Longer run times cause an increase in the current, resulting in poor band migration or a melted gel. We recommend that you run single comb gels for 25-30 min (double comb gels 15-20 min) for straighter patterns. Do not run single comb gels longer than 40 minutes (20 minutes for double comb), or the gel will be damaged and resolution will be poor.
- Voltage or current too high. This should not be an issue with the E-Gel PowerBase power supply, which is pre-set with the proper conditions. However, researchers using the old E-Gel Base (the one that plugged into a separate power supply) should ensure that they run the gel at 60 to 70 volts (constant voltage) or 40-50 mA (constant current). Do not allow the current to exceed 60 mA.
- For E-Gel 96 Agarose Gels being run on an E-Base device, be sure you are running on the EG program rather than the EP program designed for E-PAGE gels.
- The gel was not electrophoresed immediately after sample loading (for best results, run gel within 1 min of loading).
- The gel may have been used beyond its expiration date. Check the expiration date.
Find additional tips, troubleshooting help, and resources within our
Nucleic Acid Gel Electrophoresis and Blotting Support Center.