Related Experiment Video
Updated: Aug 7, 2026
10:52
Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
Design and implementation of a new electrodynamic ion funnel
T Kim1, A V Tolmachev, R Harkewicz
1Environmental Molecular Sciences Laboratory, Richland, Washington 99352, USA.
Analytical Chemistry
|June 14, 2000
Summary
A novel electrodynamic ion funnel enhances ion transmission and sensitivity for mass spectrometry. This improved interface design, featuring reduced electrode spacing, boosts the detection of peptides and proteins.
Area of Science:
- Analytical Chemistry
- Mass Spectrometry Instrumentation
Background:
- Atmospheric pressure ion sources, such as electrospray ionization (ESI), are crucial for mass spectrometry.
- Interface regions between ion sources and mass analyzers often face challenges in ion transmission and sensitivity, particularly for low-mass analytes.
Purpose of the Study:
- To develop and evaluate a new electrodynamic (rf) ion funnel for improved ion transmission and sensitivity.
- To investigate the impact of reduced electrode dimensions and spacing on ion funnel performance.
- To explore the operational modes of the ion funnel for selective ion transmission.
Main Methods:
- Design and fabrication of a new ion funnel with reduced ring electrode thickness (0.5 mm) and spacing.
- Evaluation of ion transmission efficiency and sensitivity using electrosprayed peptides and proteins.
- Comparison of performance against standard interface designs.
- Investigation of two distinct operational modes (low-rf and high-rf amplitude scans).
Main Results:
- The new ion funnel demonstrated significant improvements in low-mass transmission (m/z >200) and overall sensitivity.
- Transmission efficiencies for peptides and proteins ranged from 50-60% of total incoming currents.
- Transmitted ion currents were substantially higher (30-56x for peptides, 18-22x for proteins) compared to standard interfaces.
- Reduced electrode spacing was identified as the primary factor for improved ion transmission.
- Two operational modes allowed for the transmission of fragile complexes or enhanced adduct removal/dissociation.
Conclusions:
- The developed electrodynamic ion funnel offers superior performance for atmospheric pressure ionization mass spectrometry.
- The design's key innovation lies in the reduced spacing of ring electrodes, enhancing ion transmission efficiency.
- The dual-mode operation provides versatility for analyzing different types of analytes and optimizing data quality.
Related Concept Videos
01:15Van de Graaff Generator
Van de Graaff generators (or Van de Graaffs) are devices used to demonstrate high voltage due to static electricity that can also be used for research. Robert Van de Graaff first built one in 1931 (based on original suggestions by Lord Kelvin) for use in nuclear physics research.
Van de Graaff uses both smooth and pointed surfaces, conductors, and insulators to generate large static charges and, hence, large voltages. A substantial excess charge can be deposited on the sphere because it moves...
Van de Graaff uses both smooth and pointed surfaces, conductors, and insulators to generate large static charges and, hence, large voltages. A substantial excess charge can be deposited on the sphere because it moves...
01:23Faraday Disk Dynamo
A Faraday disk dynamo is a DC generator, producing an emf that is constant in time. It consists of a conducting disk that rotates with a constant angular velocity in the magnetic field, perpendicular to the disk's plane. The rotation of the disk causes a change in magnetic flux, which induces an emf, causing opposite charges to develop on the rim and in the center of the disk. The polarity of the induced emf can be determined by the direction of the magnetic field and the direction of the...
01:19Mass Analyzers: Common Types
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...
01:20Capillary Electrophoresis: Instrumentation
Capillary electrophoresis instrumentation typically consists of several key components. A high-voltage power supply generates the electric field necessary for the separation by connecting to an anode (the positively charged electrode) and a cathode (the negatively charged electrode) located in buffer reservoirs at each end of the capillary tube. The system includes a sample vial, a fused silica capillary tube coated with polyimide for mechanical strength through which the sample components...