A Gated TIMS FTICR MS Instrument to Decipher Isomeric Content of Complex Organic Mixtures.

Modern research faces increasingly complex materials with a constant need for new analytical strategies that can provide deeper levels of chemical insight. Ultrahigh resolution mass spectrometry (MS), particularly Fourier transform ion cyclotron resonance (FTICR) MS, has provided a robust analytical foundation. However, MS alone offers limited structural information.

Tutorial and comprehensive computational study of acceptance and transmission of sinusoidal and digital ion guides.

A quadrupoles acceptance is a measure of its ability to catch ions with certain trajectories. One way to calculate acceptance is the method of ellipses. The method arose partly from a simplification that trajectories could be calculated for an electrode axis independently of others.

Digital Waveform Technology and the Next Generation of Mass Spectrometers.

Ion traps and guides are integral parts of current commercial mass spectrometers. They are currently operated with sinusoidal waveform technology that has been developed over many years. Recently, digital waveform technology has begun to emerge and promises to supplant its older cousin because it presents new capabilities that result from the ability to instantaneously switch the frequency and duty cycle of the waveforms.

Methodology and Characterization of Isolation and Preconcentration in a Gas-Filled Digital Linear Ion Guide.

Digital operation of linear ion guides allows them to operate as traps and mass filters by modulating the duty cycles of the two driving waveforms. A gas-filled (5 mTorr) digitally driven quadrupole ion guide was used to demonstrate ion isolation and preconcentration. These abilities allow ion trapping mass spectrometers to be filled to capacity with only ions in the range of interest at essentially any value of m/z.

Computational Analysis of Quadrupole Mass Filters Employing Nontraditional Waveforms.

Quadrupole mass filters using non-sinusoidal driving potentials present exciting opportunities for new functionality. Predicting figures of merit like resolving power and transmission efficiency helps characterize these emerging devices. To this end, matrix methods of solving the Hill equation of ion motion are employed to calculate stability diagrams and pseudopotential well depth maps in the a,q plane for arbitrary waveforms.

Development of MS(n) in digitally operated linear ion guides.

This publication demonstrates the use of digital waveform manipulation in linear ion guides to trap isolated ions and fragment them before mass analysis by time-of-flight mass spectrometry (TOF-MS). Ion trapping and collection was performed by waveform duty cycle manipulation to create a negative axial potential between the rods and the end-cap electrodes. Ion isolation can be performed by duty cycle manipulation to narrow the range of stable masses while continuing to axially trap the ions.

Development of a GC x GC-TOFMS method using SPME to determine volatile compounds in cacao beans.

A method to analyze volatile compounds from cacao beans has been developed and evaluated. The method utilizes solid phase micro extraction (SPME) sampling followed by comprehensive 2-D (GC x GC) coupled with TOFMS. For the SPME procedure, a polydimethyl siloxane/divinyl benzene (PDMS/DVB) fiber was implemented.