Techniques and devices are provided related to insert assemblies that may be used in conjunction with microfluidic devices. In one embodiment, the insert assemblies include a functional material, such as a solid stationary phase, that may be coupled to a microfluidic pathway via the insert assembly. In this manner, solid stationary phase materials that may be challenging to directly apply to a microfluidic device may be separately enclosed inside the insert element prior to assembly into a microfluidic device, such as a microfluidic chip.