# Transfer conditions and transmission bias in capillaries of vacuum interfaces

## TL;DR

This study models ion transfer in vacuum capillaries of electrospray sources, analyzing flow dynamics, thermodynamical conditions, and transfer biases to improve understanding of ion transmission efficiency.

## Contribution

It introduces a detailed simulation approach for ion transfer in capillaries, including scaling relations and bias predictions based on ion mobility and composition.

## Key findings

- Ion transfer varies strongly with capillary size and temperature.
- Scaling relations effectively predict mass flow and ion current.
- Transfer bias depends on ion mobility differences and ion composition.

## Abstract

A detailed study of the transfer of ions in transfer capillaries of electrospray ion sources is presented. The laminar flow field for various capillary sizes and wall temperatures is calculated. It forms the base of ion transfer simulation of a large number of ions with space charge. This allows to study the thermodynamical conditions of the ions during transfer, which are found to vary strongly with the capillary dimensions. The dependence of mass flow and ion current on the size of the capillary is presented. Simple scaling relations are derived and tested. The method also allows to predict a transfer bias between different ion species depending on the difference in ion mobility and the composition of transferred ions.