Inline monitoring of high ammonia concentrations in methanol with a customized 3D printed flow cell

Abstract A novel system for inline monitoring of ammonia (NH 3 ) suitable methanol is presented. An optical sensor with a response time t 90 33 s was combined tailor-made, 3D printed flow cell and allowed efficient measurements under continuous flow. The includes fluorescent indicator dye that physically immobilized into polyurethane hydrogel. protective layer made hydrophobic polyether sulfone (PES) shields the sensitive material against interfering substances guarantees long-term stability in methanol. can be read out via compact phase fluorimeter. Measurements are enabled by manufactured selective laser melting (SLM) stainless steel. Stainless steel chosen due to its good heat transfer properties relatively chemical resistance NH were successfully carried concentrations between 0.3 5.6 mol L ? 1 at 25 °C up 80 °C. Additionally, different flow-rates (0.5–2.0 mL min ), varying internal pressure bar) as well reversibility 60 studied detail. did not degrade indicated sufficient signal low drift over period two weeks, thus indicating high potential set-up real-time applications. Graphical abstract