The remaining buffer assures an immediate start of the flow in all subsequent steps. It should not be pushed out. The cleared sample should be loaded to the cartridge by gravity flow. The maximum flow rates and the flow by gravity are given for the different cartridges in table 4. It removes all contaminating substances.
Washing is performed, in principle, like the equilibration step.
Minimum volumes and maximum flow rates are given in table 4. An additional amount of elution buffer equal to the dead volume of a cartridge can be added to maximize yield. If only small amounts of nucleic acids are present, the pH should be adjusted to 5.2 before starting the precipitation step. Step of the procedure 1. Binding of sample no restrictions 3.