Semi-preparative, multi-solvent pumps designed for use in Gilson's HPLC Systems accommodating flow rates ranging from 0.15 mL/min to 30 mL/min at pressures up to 8,700 psi (600 bar) and with columns up to 20 mm ID. Dual-piston pumps for semipreparative and preparative chromatography. Feature a variable-volume, dynamic mixer for optimized gradient performance. Milligram-level sample mass throughput per injection: >50 mg with a 20 mm ID column Easy linear transposition from analytical to preparative HPLC methods on a 4 to 20 mm ID column packed with high-efficiency stationary phases Solvent selection on each pump with optional four-solvent valve (up to eight solvents) Control from 331 Master Pump: flow-rate gradient, four-solvent selection and step gradient (additional valve), composition gradient (one or two additional pumps), sample-injection pump, UV/VIS detector, and electrical input/output contacts with any other associated equipment Keypad control: safety files (pressure limits, emergency signal and power failure); anomaly processing procedures with related outcomes; GLP functions: solvent consumption, diagnostic helps, maintenance logs, leak test, piston seal installation, mixing test and audit trail TRILUTION® Software provides control within a complete prep workstation; includes data processing and results reporting