A Composable 3D-Printed Platform for Rapid Sequential Sample Injection in Mass Spectrometry

Abstract We developed a composable 3D-printed platform for rapid sequential sample injection in mass spectrometry (MS). The platform works in a well plate-like format and allows direct loading of discrete sample droplets by micropipette or automated liquid handling. Droplets are separated by air gaps during transport and are directly coupled to MS through capillary vibrating sharp-edge spray ionization (cVSSI). Liquid-infused surface treatment was used to improve compatibility of the 3D-printed microchannels with MS analysis. The platform was evaluated for device operation, throughput, quantitative performance, and carryover. A throughput of ∼20 s per sample was achieved at 50 μL/min. Quantitative analysis of lysine gave a linear response with R2 = 0.9986, and carryover was evaluated across chemically distinct small molecules. These results demonstrate that the platform supports air-separated droplet transport, rapid sequential analysis of different samples, and quantitative MS measurements in a simple, modular, and customizable format.