Microfluidic Gradient Formation for Nanoflow Chip LC

We report a method for forming a nanoflow liquid chromatography (nano-LC) gradient using a single fluid pump at flow rates below 1 mu L/min by passively forming a gradient on a microfluidic device. This device works together with an Agilent HPLC-Chip to perform high-throughput nanoflow liquid chromatography/mass spectrometry (nano-LC/MS)The nanoflow gradient delay time is reduced from several minutes for a commercial LC nanoflow pump to only a few seconds with this microfluidic device, thus shortening the total analysis time and increasing the analysis throughput. With this microfluidic device, a nano-LC solvent delivery system can be greatly simplified and have increased robustness, reliability, reduced waste, and ease of use.