Coupling microchip pressure regulators with chipHPLC as a step toward fully portable analysis system

Herein the coupling of a miniaturized, nanoliter scaled, pressure regulator (chipPR), and a chipHPLC device is introduced. The active temperature based flow control of the chipPR is able to generate rapid pressure changes and therefore enables on-chip pinched injection and flow gradients with reduced instrumental effort and minimal dead volumes. The functionality of the chipPR empowered chipHLPC device was demonstrated with high-speed HPLC-separations applying fluorescence and electrospray mass spectrometry (ESI-MS) detection. The system shows excellent long-term stability of chromatography integrity (retention times with RSD of 0.44-0.91%) due to the integration of a PID feedback regulation. This first chip-based HPLC device equipped with chipPRs enables precise flow control with significantly reduced technical effort compared to the state-of-the-art.