Related Experiment Video
Updated: Sep 17, 2025
06:53
Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
8.8K
Dual-Channel Off-Axis Ion Funnel With a Deflection Electrode
Mengfei Shan1, La Chen1,2, Jun Wang1
1The Research Institute of Advanced Technologies, Ningbo University, Ningbo, China.
Rapid Communications in Mass Spectrometry : RCM
|July 1, 2025
Summary
A novel dual-channel off-axis ion funnel with deflection electrode (DC-OFIDE) improves electrospray ionization mass spectrometry (ESI-MS) by enhancing ion transmission and reducing noise for complex samples.
Area of Science:
- Analytical Chemistry
- Mass Spectrometry Instrumentation
Background:
- Electrospray ionization mass spectrometry (ESI-MS) faces challenges with ion loss and contamination due to under-expanded supersonic jets and residual droplets.
- These issues reduce ion transmission efficiency and increase chemical noise, compromising analytical accuracy.
Purpose of the Study:
- To develop and evaluate a dual-channel off-axis ion funnel with a deflection electrode (DC-OFIDE) to overcome ESI-MS limitations.
- To improve ion transmission efficiency and chemical noise suppression in ESI-MS systems.
Main Methods:
- Developed a DC-OFIDE integrating an ion drift channel (IDC), an ion funnel channel (IFC), and a deflection electrode.
- Utilized a retarding axial field to prolong ion residence time for efficient transfer.
- Incorporated an enlarged entrance aperture (18 mm) for compatibility with high-conductance sample introduction.
Main Results:
- DC-OFIDE achieved a threefold increase in caffeine ion intensity and a broader m/z transmission window compared to conventional ion funnels (CIF).
- Demonstrated robust neutral and droplet suppression, retaining 80% ion intensity with tripled serum volume.
- Reduced baseline noise by 36%-82% in drug screening of hair samples, with a quadrupled signal-to-noise ratio for 6-monoacetylmorphine.
Conclusions:
- The DC-OFIDE significantly enhances ion transmission efficiency and chemical noise suppression in ESI-MS.
- This technology shows potential for high-fidelity analysis of complex biological and forensic samples.
Related Concept Videos
01:19Mass Analyzers: Common Types
717
The quadrupole mass analyzer consists of four cylindrical metal rods arranged in a diamond carrying a DC voltage and a radio-frequency AC voltage. The motion of ions through the quadrupole depends on the field strength, causing only ions of a certain m/z to resonate successfully and strike the detector at a given field strength. Though the transmission rate for these analyzers is high, the exact elemental composition of the sample is not determined because of low resolution; however, they are...
717
01:28Induced Electric Dipoles
4.4K
A permanent electric dipole orients itself along an external electric field. This rotation can be quantified by defining the potential energy because the external torque does work in rotating it. Then, the potential energy is minimum at the parallel configuration and maximum at the antiparallel configuration. While the former is a stable equilibrium, the latter is an unstable equilibrium.
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
4.4K
01:31Dielectric Polarization in a Capacitor
5.1K
The presence of a dielectric medium in a capacitor not only changes the voltage and capacitance but also affects the electric field. In general, dielectrics can be of two types: polar and nonpolar. In a polar dielectric, the positive and negative charges in the molecules are separated by a distance and hence have a permanent dipole moment. In contrast, no such charge separation exists in a nonpolar dielectric, however the nonpolar molecules get polarized in the presence of an external electric...
5.1K
01:17Controlled-Potential Coulometry: Electrolytic Methods
287
Controlled-potential coulometry, also known as potentiostatic coulometry, employs a three-electrode system in which the working electrode's potential is precisely regulated using a potentiostat. Platinum working electrodes are utilized for positive potentials, while mercury pool electrodes are favored for extremely negative potentials. The platinum counter electrode is separated from the analyte using a membrane or salt bridge to avoid interference in the analysis.
The chosen potential...
The chosen potential...
287
01:27Induced Electric Fields: Applications
1.9K
An important distinction exists between the electric field induced by a changing magnetic field and the electrostatic field produced by a fixed charge distribution. Specifically, the induced electric field is nonconservative because it does not work in moving a charge over a closed path. In contrast, the electrostatic field is conservative and does no net work over a closed path. Hence, electric potential can be associated with the electrostatic field but not the induced field. The following...
1.9K
01:30Electric Field of Two Equal and Opposite Charges
6.3K
Atoms generally contain the same number of positively and negatively charged particles, protons, and electrons. Hence, they are electrically neutral. However, the centers of the positive and negative charges do not always coincide. In such a scenario, the electric field of an atom may not be zero.
A separation of the positive and negative charges can lead to a weak, remnant effect of the positive and negative charges. The expectation is that the more the distance between the positive and...
A separation of the positive and negative charges can lead to a weak, remnant effect of the positive and negative charges. The expectation is that the more the distance between the positive and...
6.3K