Multi-Electrospray Ion Source for Mass Spectrometry
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Solution Overview
Problem
Conventional electrospray ionization sources for mass spectrometry face interference issues due to the proximity of multiple electrospray emitters, leading to reduced electrospray current and ion signal magnitude, as well as challenges in centering ion streams within the mass spectrometer, which are typically narrow.
Innovation Solution
A multi-electrospray ion source system is designed with a plurality of electrospray emitters arranged such that each emitter's emission tip is at a non-zero angle relative to the central longitudinal axis of a mixing chamber, and spaced at least 3 mm apart to minimize interference, with a mixing chamber and inlets configured to receive and combine charged particles from each emitter, and a heater to aid in desolvation, allowing for efficient ion transfer to a mass spectrometer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple electrospray emitters are placed in proximity to increase ion production, then the quantity of ions is improved, but interference between emitters reduces electrospray current and ion signal magnitude
Solution Approach 1:
The ion source is divided into multiple independent electrospray emitters, each operating separately with sufficient spacing (at least 3 mm apart) to minimize interference while collectively increasing ion production. The mixing chamber segments the ion streams from individual emitters before combining them.
Solution Approach 2:
Emitters are arranged in a three-dimensional configuration rather than a simple linear array, with non-zero angles relative to the central longitudinal axis of the mixing chamber. This spatial arrangement optimizes ion collection efficiency while maintaining adequate separation distances.
2Quantity of substance
If multiple electrospray emitters are used to increase ion signal, then the quantity of ions is improved, but centering ion streams in the narrow mass spectrometer inlet becomes more difficult
Solution Approach 1:
Multiple ion streams from separate emitters are merged within a single mixing chamber that funnels all streams toward a common central outlet. This consolidation simplifies alignment by providing a single exit path to the mass spectrometer inlet rather than requiring precise alignment of multiple separate beams.
Solution Approach 2:
The mixing chamber is designed with an asymmetric geometry where individual emitter inlets are positioned at non-zero angles relative to the central longitudinal axis. This asymmetric arrangement naturally guides divergent ion streams toward the central outlet, facilitating automatic centering without complex alignment mechanisms.
3Reliability
If emitter spacing is increased to reduce interference, then electrospray current is improved, but the device complexity and size increase
Solution Approach 1:
The mixing chamber serves multiple functions simultaneously: it separates ion streams from individual emitters, combines them into a single unified beam, provides thermal desolvation through heating, and guides the combined stream to the mass spectrometer inlet. This multi-functionality reduces the need for additional components despite the multi-emitter configuration.
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 configuration enhances the efficiency of ion inletting into mass spectrometers by reducing interference and improving ion signal magnitude, enabling better detection and quantification of analytes, even at low concentrations, by effectively managing the electrospray current and stream alignment.
Implementation Method 1
The optionally heated drying gas causes the solvent in the droplets to evaporate
Implementation Method 2
a heater in thermal contact with at least a portion of the mixing chamber
Implementation Method 3
The electric field induced between the electrode and the conducting liquid initially causes a Taylor cone to form at the tip of the tube where the field becomes concentrated
Implementation Method 4
The conventional electrospray process involves breaking the meniscus of a charged liquid formed at the end of the capillary tube into fine droplets using an electric field. The electric field induced between the electrode and the conducting liquid initially causes a Taylor cone to form at the tip of the tube where the field becomes concentrated. Fluctuations cause the cone tip to break up into fine droplets which are sprayed, under the influence of the electric field, into an ionization compartment
Implementation Method 5
a heater in thermal contact with at least a portion of the mixing chamber
Data Source
AI summary
An electrospray ion source for a mass spectrometer comprises: (i) a plurality of N electrospray emitters within an ionization compartment, wherein N≥2; (ii) a mixing chamber; (iii) a plurality of N inlets, each inlet comprising a conduit configured to receive charged particles from a respective one of the electrospray emitters and to emit the charged particles into the mixing chamber; (iv) an outlet port either facing or within an intermediate-vacuum compartment; and (v) a heater in thermal contact with at least a portion of the mixing chamber.