Ion Source Apparatus for CO2 Chromatography Mass Spectrometry Interface

The patent removes the back pressure regulator from the system entirely, extracting the problematic component that caused peak broadening. Instead of using a BPR, the system relies on the inherent pressure characteristics of the capillary column and uses a make-up flow to maintain appropriate pressure conditions, thereby preserving chromatographic efficiency while still achieving stable pressure operation.

The patent introduces a make-up flow as an intermediary substance that mediates between the chromatography column and mass spectrometer. This make-up flow serves multiple functions: it maintains pressure without causing peak broadening, ensures proper analyte transport, and facilitates ionization in the mass spectrometer, thereby resolving the contradiction between pressure stabilization and chromatographic efficiency.

The patent changes the flow rate parameter to optimized low flow rates suitable for microfluidic applications, which improves sensitivity by reducing background noise and enhancing signal-to-noise ratio. The make-up flow compensates for the reduced main flow rate, ensuring that analyte transport remains reliable and efficient throughout the system.

The make-up flow acts as an intermediary that ensures reliable analyte transport despite the reduced main flow rate. It provides the necessary carrier function for analytes through the capillary column and into the mass spectrometer, maintaining transport reliability even at microfluidic flow rates where the primary mobile phase flow is minimal.

The patent uses a make-up flow as an intermediary substance that facilitates ionization in the electrospray ion source. This make-up flow, which may contain ionization-promoting additives, mixes with the carbon dioxide mobile phase and provides the necessary conditions for efficient analyte ionization, thereby resolving the contradiction between achieving chromatographic separation with CO2 and enabling effective ionization in the mass spectrometer.

The patent modifies the composition parameter of the mobile phase by introducing a make-up flow that contains ionization-promoting substances. This parameter change enables effective ionization in the electrospray ion source while maintaining carbon dioxide as the primary mobile phase for chromatographic separation, thus resolving the ionization difficulty without sacrificing separation performance.

The patent merges the make-up flow introduction with the existing mobile phase flow path in a streamlined manner. The make-up flow is introduced through a simple T-connector or similar minimal plumbing configuration, combining it with the mobile phase downstream of the column. This merging approach achieves improved ionization efficiency while minimizing additional plumbing complexity and avoiding the need for complex high-pressure fluid handling systems.

The patent employs simple, inexpensive plumbing components such as T-connectors and standard tubing for the make-up flow introduction, rather than requiring expensive, complex high-pressure plumbing systems. This approach uses readily available, low-cost components that are easy to install and maintain, thereby improving ionization efficiency without significantly increasing device complexity or cost.