Droplet Analysis System Using Liquid Chromatography and Mass Spectrometry for Enzyme Inhibition Assay

In this work, the combination of droplet array chip with LC/MS was firstly achieved, for providing a high-separation-resolution and high-information-content detection method for analysis of complex compositions in nanoliter droplets. A novel interface for capillary LC and droplet array chip with outstanding flexibility in accurate addressing of interesting droplets on demand was developed, with which multistep operations including enzyme inhibition reaction in nanoliter droplet, 4-nL sample injection, high-resolution separation with HPLC, and label-free detection with ESI-MS were successfully realized. The present system was further applied in the enzyme inhibition assay to demonstrate its potential feasibility in low-consumption drug screening.