Abstract: A device and method for controlling capillary injection volume is disclosed. The device is a capillary surrounded at one end by an outer jacket which is filled with a wash liquid. The outer jacket and the capillary can move relative to each other along their longitudinal axes. The open end of the capillary is moved out of the wash liquid and is dipped into a liquid sample causing some of the sample to enter the capillary. As the capillary is withdrawn from the sample, the outer jacket moves to cover the capillary until the open end is completely immersed within the wash liquid, thereby preventing an unpredictable additional volume of sample from being injected into the capillary by the residual sample solution adhering to the capillary.