4.3.1.1 .1 Hydrodynamic Injection

Hydrodynamic injection introduces a sample by applying a pressure on the sample reservoir. This physically forces solution through the capillary. The volume of sample loaded is independent of the sample matrix; instead, the volume depends on the details of the system, such as capillary dimensions, the viscosity of the buffer, the pressure applied, and the amount of time that pressure was applied. Pressures and times generally range from 25-100 mbar and 0.5-5 seconds.

Figure 4.5 Hydrodynamic injection setup.

Similarly, hydrodynamic injection can be performed by siphoning, or raising the input reservoir 5-10cm above the output reservoir while keeping the levels of each equal. This technique is generally employed when the equipment necessary for pressure injection is unavailable.