The following describes the fluidic instrumental setup, including all components and connections. The setup is shown schematically in Fig. A and can be divided into one section for continuous microreactor operation and another section for online LC/MS-analysis, which can be performed by either a conventional or a chipHPLC approach. All system flows were generated using three HPLC pumps in combination. The first pump provided the sample stream through the microreactor at a relatively low flowrate (0.2 µl/min, 40:60 ACN:H2O (v/v) + 50 mM MES-buffer pH 6.0; LC-20AD, Shimadzu, Kyoto, Japan). To provide the respective reactant feed, either a sample loop was connected to an additional valve (e.g., 0.3-1 ml sample reservoir for long-term monitoring experiments; refillable via an external PEEK needle port adapter) or an autosampler to facilitate sample variation during individual runs (40 µl loop, G1377A, Agilent). In certain runs, a second pump was used for sample dilution past the microreactor positions before online analysis (1:10 dilution, 1260 Infinity isocratic HPLC pump, Agilent). The final pump was utilised in the analytical section to generate the eluent flow for LC/MS-analysis using a binary pump (600 µl/min, 70:30 ACN:H2O (v/v); 1260 Infinity binary HPLC pump, Agilent). The fluidic circuit was realised by combining multiple Nanovolume valves (either two-position or selector valves, with 360 µm connections, Cheminert, VICI AG, Schenkon, Switzerland), which were connected through commercially available PEEK and FS capillary tubing (mostly 360 µm OD, 50-100 µm ID, VICI AG) and high-pressure PEEK fittings on a custom metal stage. The microreactors, connected between the two selector valves, can be selected from ten different positions by switching the fluidic path of the two valves for increased flexibility during automated reaction monitoring. For online analysis, the reactor stream was guided through an additional 2-position valve (either 0.2 or 2 µl injection loop, depending on whether a reactant sample feed dilution was used), which could be sequentially sampled onto a chromatographic column (Zorbax Eclipse Plus C18, 4.6x100 mm, 3.5 µm, Agilent) and detected by an ESI-MS-system (AmaZon SL, Bruker Daltonics GmbH, Bremen, Germany). Electric actuators controlled all valves, while the operation was automated by a Clarity chromatography data station combined with a Colibrick A/D converter box (DataApex, Prague, Czech Republic). These modules enhanced pump control and pressure monitoring and enabled automated injection sequences of the reactor effluent for LC/MS-detection. This included sampling every 10-15 min and starting acquisitions by connecting to the auxiliary ports of the mass spectrometer. In addition, it was possible to sequentially address multiple microreactor positions in single runs with individual reactant sampling by controlling the selector valves and the connected autosampler. Further information about the instrumental setup and a detailed description of the automation principle, auxiliary connections, and sequencing for multi-reactor operation can be found in the ESI in section S2 & S3.