Two-phase flushing systems and methods

A method, comprising:

• moving a valve to a first position to fluidly connect a first reagent reservoir containing a first reagent to a flow cell, the flow cell positioned at a receptacle of a system and comprising an outlet fluidly coupled to a waste reservoir associated with the system;
• flowing the first reagent from the first reagent reservoir into the flow cell to perform a biochemical reaction;
• moving the valve to a second position to fluidly connect gas to the flow cell;
• flowing the gas into the flow cell to expel at least a portion of the first reagent from the biochemical reaction from the flow cell;
• moving the valve to a third position to fluidly connect a buffer reagent reservoir containing a buffer reagent to the flow cell;
• flowing the buffer reagent into the flow cell;
• moving the valve to the second position to fluidly connect the gas to the flow cell;
• flowing the gas to the flow cell to expel at least a portion of the buffer reagent from the flow cell;
• moving the valve to the third position to fluidly connect the buffer reagent reservoir to the flow cell;
• flowing the buffer reagent into the flow cell;
• and
• moving the valve to a fourth position to fluidly connect a second reagent reservoir containing a second reagent to the flow cell.