A simple laboratory setup is described for performing green liquid chromatography in a nanocolumn with a great potential to minimize solvent consumption and waste production as required in green chemistry. The system consists of a high-pressure syringe fixed in vertical position and with weight. This setup acts as a constant-pressure pump. Samples are injected by short switch of a two-way six-port injection valve equipped with an external sample loop. Isocratic separation of EPA 8330 standards was performed. The relative standard deviations of retention times below 1 % demonstrate a constant mobile phase flow for several hours.