Horizontal gel electrophoresis procedure. However if the gel bands are too faint then the staining procedure should be adjusted so that there is less de-staining. Use sample template and carefully move the wells to the application zone. Electrophoresis Standard Operating Procedures General Only trained and qualified personnel are permitted to operate gel electrophoresis equipment. . Figure: Principle of polyacrylamide gel electrophoresis, Image source: DOI: 10. Westermeier (1) and Burgess (2) have recently reported regarding frequently made mistakes in electrophoresis and important but little known artifacts in protein biochemistry. One end of the chamber carries a positive charge, while the other end carries a negative charge, created by the running buffer present in the chamber. Changes in load, equipment failure, or power surges could raise the voltage at any time. APPEARS TO HAVE NEVER BEEN USED. There are many types of electrophoresis units, but the horizontal electrophoresis unit is the most commonly used unit for separating DNA molecules on agarose gels.