Segmented fluidic mixing

A microfluidic device, comprising:

• a. a generally planar substrate comprising a microfluidic network therein, the microfluidic network comprising:
• i. a distal gas chamber configured to adjust a pressure of a distal gas within at least a portion of the microfluidic network;
• ii. a microfluidic channel extending distally from an application zone to the distal gas chamber, the application zone configured to receive a sample liquid therein;
• and
• iii. a separation gas chamber in communication with the microfluidic channel via a separation gas channel that intersects the microfluidic channel at a separation gas introduction location, the separation gas chamber configured to adjust a pressure of a separation gas within at least a portion of the microfluidic network;
• wherein, the sample liquid is configured to flow from the application zone through at least a portion of the microfluidic channel to a capillary stop located distal to the separation gas introduction location, such that introduction of the separation gas into the microfluidic channel thereafter forms a separation gas bubble within the microfluidic channel that separates the sample liquid therein into i) a liquid segment located distal to the separation gas bubble, and ii) a remaining volume of sample liquid located proximal to the separation gas bubble, the liquid segment forming i) a distal gas-liquid interface disposed between the distal gas and the liquid segment, and ii) a proximal gas-liquid interface disposed between the separating gas and the liquid segment.