to a pressure indicating meter 120 the microfluidic device 116 was immersed in a beaker 122 filled with water 124 to monitor any leakage at the interconnect which would lead to the formation of air bubbles at the interconnect point the capillary 122 connected to the outlet of the microchannel device 116 was capped plug 126 so that no gas could escape from the outlet side thus any compression of the syringe 112 would lead to an increase in pressure inside the microfluidic device and would show up as increasing pressure reading on the indicating meter 120 a syringe pump was used in the syringe apparatus 112 to move the syringe plunger at a constant controlled rate and generate the high pressures at which the testing was to be carried out a number of interconnects were fabricated and tested for leakage at high pressures by pressurizing and maintaining the system at the test pressure for several hours to observe any pressure loss in the system this step was necessary to ensure that there were no visually unobservable minute air bubbles that were leaking out of the system unlike the method based on the verification of the linear relationship of pressure v s inverse volume ideal gas law used by others this procedure is more accurate for the tested pressures since the ideal gas law is not valid at the high pressures that were applied to the interconnects during this study results from the pressure tests showed that the unreinforced interconnects could operate up to a pressure of at least 315 psi 21 43 atm without failure over extended periods of time this is a significant improvement over the experimentally verified values of 190 kpa 1 87 atm and 30 psi 2 04 atm reported in the literature.