4.5.5.1.1.1 Sheath Flow Interface

Smith, et al. invented the tri-axial capillary sprayer, similar to the one shown below.

Figure 4.12 Sheath flow interface.

Solvent flows between the capillary and the sprayer tip, and combines with the capillary solution immediately before the nebulizing gas. In this way, a hydraulic flow independent of the EOF is provided by the sheath solvent.

The major disadvantage of the sheath flow interface is the fact that the sample is necessarily diluted by the sheath solvent. Despite this, the sheath flow interface is one of the most reliable methods of interfacing CE and MS, although several alternative methods exist but are not “as robust,” according to Agilent literature. (It should be noted that Agilent possesses the distribution rights on the tri-axial sheath.)