Chromatograms of blank measurements, all of them with a derivatization agent, together with a chromatogram of standard of 20 ppm of nucleobases for comparison depicted in panel A. Panels B and C: chromatographic record of a cell filled with nitrogen exposed to a plasma and a record of a cell from a laser shock wave experiment not exposed to plasma, both washed with water; panel D: chromatogram of a cell touched with fingers without gloves, and panel E: record of water after washing of a montmorillonite catalyst. Numbers 1–9 mark manifold products of mutual reactions in derivatization agent.