Multipass CCS Refiner: A Web Application for Accurate Collision Cross Section Calibration in Cyclic Ion Mobility-Mass Spectrometry.

In this paper, we present the Multipass CCS Refiner, an R application for calibrating multipass collision cross section (CCS) measurements with cyclic ion mobility spectrometry (cIMS). The Multipass CCS Refiner combines the necessary tools for calculating accurate CCS measurements from multipass cIMS experiments into a user-friendly web-based Shiny interface accessible regardless of programming knowledge. The application provides a suite of functions for calculating accurate arrival times, automated pass counting approximation, correction of arrival time perturbations during separation, constructing calibration curves unique to specific instrument settings, separating fine mobility features, and a variety of visualization tools. Code for the application is structured to be easily modified to meet the user's needs. The Multipass CCS Refiner implements the calibration approach described by Lin and Costello to reduce the need for carefully selected separation times while accounting for artifacts underlying fluctuations in measured ion arrival times. The application is showcased with downloadable data files of commonly used standards, which can be run in the app directly or edited with user experimental data.