For the final integrated chip-based separations, a bonded borosilicate glass chip was utilised, which was manufactured externally according to an in-house protocol (by iX-factory GmbH, now part of Micronit GmbH, Dortmund, Germany), including conventional photolithography, wet etching, and subsequent high-temperature fusion bonding (a process also described elsewhere, chip dimensions: 45 x 10 x 2.2 mm). In general, the chip design, as shown in Fig. , consists of an integrated injection-cross connected to a slurry-packed chromatographic column located in a separation channel with a semicircular cross-section (35 mm length, 90 µm max width, 40 µm depth). At both channel ends, photopolymerised frits were integrated as particle-retaining structures. As stationary phase material, either XBridge (C18, ∅ 2.5 µm, Waters, Milford, USA) or Poroshell particles (C18, ∅ 2.7 µm, Agilent, Santa Clara, USA) were used and packed into the separation column through an additional packing channel. The packing channel was then sealed with a photopolymerised plug, and a monolithic pyramidal electrospray emitter was ground and hydrophobised before use. Similar to the µreactor chip, all fluidic connections were realised by high-pressure clamps as described above. More details of the preparation steps can be found in the ESI in section S1.2. Slurry-packing: In both chip variants, the particles were integrated by slurry-packing (either for the biocatalytic material or as a separation column). The chip was positioned in an ultrasonic bath and connected to an HPLC-pump and 6-portvalve with a slurry-filled sample loop (approx. 2-3 mg/ml particle slurry). The process could be reversed for the reactor chip by flushing the reactor from the opposite direction.