Acoustic-Electrospray Ion Source for Mass Spectrometry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ionization techniques in mass spectrometry, particularly those involving ultrasound, lack stability and efficiency in ionizing samples, as they do not effectively utilize alternating voltages to enhance the ionization process.
Innovation Solution
Applying one or more pulses of acoustic energy to a fluid sample to eject a spray, combined with an alternating voltage applied using an electrode, which improves the stability and efficiency of ionizing analyte molecules by causing them to form a mist or atomized particles, potentially ionizing them as they exit the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasound is applied to eject droplets from a fluid sample, then sample introduction into mass spectrometer is achieved, but ionization stability is insufficient
Solution Approach 1:
The patent combines two ionization techniques: acoustic ejection of droplets and electrospray ionization. The acoustic transducer ejects droplets while an electrode simultaneously applies voltage to generate a spray of ionized particles. This merging of acoustic and electrical fields resolves the contradiction by achieving both stable droplet ejection and efficient ionization, as evidenced by the stable baseline and consistent ion signals observed in the mass spectrometer.
Solution Approach 2:
The patent employs periodic pulsing of acoustic energy at frequencies between 1-100 MHz to eject droplets from the fluid sample. This periodic acoustic action, synchronized with the electrospray voltage application, creates a continuous stream of ionized droplets. The periodic nature of the acoustic pulses ensures consistent droplet formation and ejection, thereby improving ionization stability while maintaining high ionization efficiency through continuous sampling.
2Productivity
If a single drop is transferred into the mass spectrometer inlet, then sample introduction is achieved, but ionization efficiency is limited
Solution Approach 1:
The patent segments the single droplet into numerous smaller droplets through the combined action of acoustic pulsing and electrospray. Instead of transferring one large droplet, the system generates a spray of many smaller droplets, each capable of being ionized and introduced into the mass spectrometer. This segmentation increases the total surface area and number of ionization events, thereby improving ionization efficiency while the continuous nature of the spray ensures operational stability.
Solution Approach 2:
The patent replaces the purely mechanical droplet transfer method with a combined acoustic-electrical system. The electrospray component uses electrical fields to generate and propel ionized droplets, substituting mechanical manipulation with electromagnetic forces. This substitution improves ionization efficiency by directly creating ions in the spray, while the stability is maintained through the controlled application of electrical fields and acoustic pulsing.
3Reliability
If acoustic energy pulses are applied to create spray, then droplet ejection is improved, but ionization stability remains insufficient without alternating voltage
Solution Approach 1:
The patent changes the electrical parameter by applying an alternating voltage (AC, RF, or pulsing DC) to the electrode instead of a static voltage. This parameter change allows the electrical field to dynamically respond to the acoustic droplet ejection, creating a stable spray pattern that is continuously ionized. The alternating voltage ensures that ions are generated efficiently throughout the spray, improving both spray stability and ionization efficiency simultaneously.
Solution Approach 2:
The patent establishes continuous ionization by maintaining a persistent electrical field through alternating voltage application while acoustic pulses continuously eject droplets. Unlike single-pulse methods, this continuous action ensures that every droplet in the spray is ionized as it forms and travels toward the mass spectrometer. The continuity of both acoustic ejection and electrical ionization creates a stable, efficient ion source with consistent signal output.
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 method enhances the stability and efficiency of ionizing samples by creating a stable spray of droplets with dimensions less than 15 μm, allowing for effective ionization and transportation of analyte ions into a mass spectrometer, improving the overall performance of mass spectrometry.
Implementation Method 1
applying one or more pulses of acoustic energy to the fluid sample to cause a spray of the fluid sample to eject from the surface of the fluid sample
Implementation Method 2
applying a voltage, for example an AC, RF or alternating voltage to the fluid sample using an electrode... The voltage optionally causes analyte molecules in said spray to ionise
Data Source
AI summary
A method of ionising a sample is provided, comprising providing a fluid sample, wherein the fluid sample contains an analyte, applying one or more pulses of acoustic energy to the fluid sample to cause a spray of the fluid sample to eject from the surface of the fluid sample, and applying an AC, RF or alternating voltage to the fluid sample using an electrode.