We demonstrate the importance a larger device footprint to accommodate on arbitrary number of world-to-chip connections for studies of complex on-chip laminar co-flow patterns. Such patterns have been used extensively in our group and elsewhere to present liquid-liquid interfaces for spatially selective precipitation processes, reactions, creation of concentration gradients, and to create nutrient rich/poor regions for patterned growth of microbial samples. The design (Figure ), featuring six inlets and one outlet, is designed to generate laminar co-flow patterns in main channel. Inlet 1 is divided into 2 channels, providing a sheath flow along the main channel walls, thus confining the other 5 streams to the middle position of the channel (Figure ). The ridge direction was perpendicular to the aperture. We chose this orientation so we could have continuous 1-D scan maps without oscillations signals that are obtained for the other orientation (as seen in Figure ). In our test, we pumped distilled water into Inlet 1 (12 mL•h -1 ) and into Inlets 3 and 5 (3 mL•h -1 ). An aqueous solution of Na2HPO4 (0.1 M) was pumped into in Inlets 2, 4 and 6 at same flow rate (3 mL•h -1 ). A separate syringe was attached to each inlet to ensure there was no flow redirection. The elevated total flow rate of QT = Q1 + Q2 + Q3 + Q4 + Q5 + Q6 = 27 mL•h -1 was operated for 4 hours without leaking. The same device maintained its integrity during repeated operation under similar flow rates for over a month, demonstrating the robust nature of the embedded ATR crystal. A 6-flow interface was established as seen in Figure . A COMSOL simulation was using the same experimental flow conditions (Figure ) predicted the same flow pattern as observed in real device. Then, we applied a 0.4 mm aperture scan the device from one side of the device to the other with step of 0.1 mm. Integration of Na2HPO4 signature bands at 1072 cm -1 provided the chemical composition of flow streams across channel (Figure ). The curve shows three flow streams comprised of Na2HPO4 from inlets 2, 4 and 6, each separated by a flow of distilled water. The integration area of Na2HPO4 absorbance bands was maximum in the centre and became reduced value in the wings despite each stream having the same concentration (Figure ). This was expected from previous studies due to a combination of the Gaussian IR beam profile provided by the spectrometer and the presence of some constant background signal reaching the detector. 9