Curved Collision Cell with Straight Section for Ion Confinement
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Solution Overview
Problem
In mass spectrometry, curved collision cells often result in ion loss due to excessive kinetic energy, leading to reduced sensitivity and analysis detriments, as ions may collide with electrodes or escape if their perpendicular kinetic energy exceeds the pseudo-potential well depth.
Innovation Solution
The incorporation of a straight section within the collision cell, allowing precursor ions to lose kinetic energy before entering a curved section, thereby preventing ion loss and enhancing ion confinement within the collision cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If curved collision cells are used to reduce overall length, then the ion path length is reduced, but ion loss increases due to excessive kinetic energy causing ions to escape or collide with electrodes
Solution Approach 1:
The collision cell is divided into a straight section and a curved section. The straight section allows ions to lose kinetic energy through collisions with background gas, while the curved section provides radial confinement. This segmentation resolves the contradiction by preparing ions in the straight section before they enter the curved section, ensuring they have reduced kinetic energy suitable for confinement.
Solution Approach 2:
The straight section performs preliminary kinetic energy reduction of ions before they enter the curved section. By allowing ions to collide with background gas in the straight section, their perpendicular kinetic energy is reduced below the pseudo-potential well depth, preventing subsequent losses in the curved section.
2Productivity
If ions enter curved collision cell with high kinetic energy, then ion path length is reduced, but sensitivity decreases due to ion loss on quadrupole electrodes
Solution Approach 1:
The collision cell is divided into a straight section and a curved section. The straight section allows ions to lose kinetic energy through collisions with background gas, while the curved section provides radial confinement. This segmentation resolves the contradiction by preparing ions in the straight section before they enter the curved section, ensuring they have reduced kinetic energy suitable for confinement.
Solution Approach 2:
The straight section performs preliminary kinetic energy reduction of ions before they enter the curved section. By allowing ions to collide with background gas in the straight section, their perpendicular kinetic energy is reduced below the pseudo-potential well depth, preventing subsequent losses in the curved section.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design significantly increases the survival rate of ions through the collision cell, improves fragmentation efficiency, and reduces the required collision cell pressure, leading to enhanced mass analysis sensitivity and reduced operational challenges.
Implementation Method 1
In a collision cell, precursor ions are fragmented by collision-induced dissociation, to produce a number of product ions
Implementation Method 2
If the kinetic energy of the ion perpendicular to the axial axis of the quadrupole is higher than the pseudo-potential well depth, it is possible for the ion to be lost on a quadrupole electrode
Data Source
AI summary
A novel curved collision cell for a mass spectrometer is described. The collision cell includes a straight section having a length that is selected to cause a precursor ion entering the straight section to lose a desired amount of kinetic energy such that when the precursor ion enters the curved section of the collision cell the precursor ion will tend to neither escape nor contact the collision cell, and thereby tending to survive its passage within the curved portion.