For several decades, different aspects of microfluidic technology have been developed in parallel in academic and private sector, with over of focus being new fabrication techniques, device designs, fluid control systems, world-to-chip interfaces and on-chip characterization. The last is arguably the most difficult since it usually involves challenging device fabrication protocol to embed probes and coupling to peripheral equipment. This is especially true for infrared (IR) spectroscopy because, other than for a few notable exceptions, 1 measurements in microchannels are usually carried out in attenuated total reflection (ATR) mode, which avoids signal attenuation by the device and analyte fluids. For examples, reversibly integrated ATR probes have been demonstrated for single point measurement leading coupling of probe light focused into to a small fixed detection zone along the flow path. The approach was successfully used to measure the kinetics of a complicated polymerization reaction by modulating reaction time by changes to flow rates, and was also compatible with other on-chip probes, but spatial-resolved measurements were not possible. Moreover, the ATR coupling to the device required highly engineered approaches and could result in dead volumes and leaks if not done accurately. Another published approach for on-chip FTIR is to fabricate the microfluidic channel structure on top of the ATR crystal. Previously we devised an approach to seal PDMS channels with a large monolithic germanium ATR crystal surface. The entire assembly could be translated mechanically to interrogate different locations on-chip. The system featured either 6 parallel channels, for channel-specific assay measurements, or a single channel device that could be translated to create one-dimensional maps along the channel length. The setup was complemented with inline reflection microscopy to monitor the formation of bacterial biofilms. Another approach to chemically image the contents of a microfluidic device with high spatial resolution in two dimensions was accomplished using a 64 × 64 pixel focal plane array (FPA) detector to sub-divide the radiation leaving a large single-bounce ATR crystal that was adhered to the bottom side of a microfluidic device. Also using a FPA, a simple Y-shape microfluidic was recently imaged using a low-cost multi-ridge silicon ATR crystal. And what is more, by changing the focal length of the last off-axis parabolic mirror with a lens, the resolution could nearly reach the diffraction limit. Such multi-grove ATR crystals distinguish themselves among other methods for integrated reflection elements for IR characterization in microscale flow chemistry devices 8 due to their ability to meet central goals of low-cost, disposable microfluidic devices without any sacrifice to sensitivity. To further reduce the system cost, our group demonstrated a method to replace the FPA with a standard single point detector. The detector recorded separate spectra based on the position of an automated scanning aperture system that selectively admitted light into different locations of a device-coupled multi-ridge ATR crystal. Independent of the detection system used previous applications of multi-ridge ATR crystals for on-chip measurements have largely relied on patterning photoresist onto the crystal sampling surface to define the entire microfluidic device. Thus, only the most simplistic microfluidic features could be realized on the available surface area, measuring approximately 1 cm 2 . Worse, spin-coated photoresists were dominated by edge bead effects, which resulted in non-uniform channel wall height and complicated the attachment of a sealing layer to enclose the channels.