Abstract: The invention describes a high-pressure syringe pump system for use in the field of HPLC, UHPLC, micro-HPLC and nano-HPLC in gradient operation. The different solvents are compressed independently by passive non-return valves, the solvent combination does not take place until at an identical pressure, and the target pressure for the initialization is achieved by a control setting with a higher delivery capacity, in which the compressibility is also taken into consideration. The changing of solvents and the flushing of the pump heads take place by way of separate inlets and outlets in the throughflow via an active multiple-position high-pressure valve which can also close the pump head and can open it via the passive non-return valve. The regulating unit and the drive motor which also serves as force sensor detect compressibility, air inclusions and leaks. Depending on the embodiment, the syringe pump heads are stabilized thermally.