Mass Spectrometry

The in-tube extraction technique for determination of volatile organic compounds in water is described.

This article presents GC–TOFMS methods developed to identify several major drug classes and chemical functionalities.

The adoption of MALDI-TOF mass spectrometry for imaging applications is a major recent development in the market. Applications lie squarely in the life sciences area, being primarily in histopathology. The market for MALDI imaging products already accounts for a significant and rapidly growing portion of the aftermarket for MALDI-TOF mass spectrometry.

First developed in the mid-1980s, matrix assisted laser desorption ionization (MALDI) added a complementary mass spectrometry ionization technique to others that were already on the market, such as electrospray ionization (ESI).

Columnist Ken Busch presents the third of a five-part series on quantitative mass spectrometry. In this installment, he focuses on an overview of regression analysis for calibration lines and curves in mass spectrometry.

The concept of portable mass spectrometry has been around for some time, but the realization of such technology has been largely limited until very recently. More than ever before, recent technological advances now make smaller, lighter, and more effective mass spectrometers possible. Such advances will lend themselves to a growing spectrum of applications as well.

In this month's installment, columnist Ken Busch continues his discussion of quantitative mass spectrometry with a look at the "cancel out" claim and some of the statistical underpinnings for the proportional comparison of instrument responses for standard knowns and unknowns.

This tutorial illustrates the most important definitions used in high-resolution mass spectrometry and clarifies the misconceptions surrounding some of the relevant terms used in this field.

In this article, the role of a triple-quadrupole mass spectrometer in performing in vitro studies of compound metabolic stability and identification of Phase I and II metabolites is demonstrated.

The list of acronyms in mass spectrometry published regularly here reflects the writings and conversations of mass spectrometrists, who use a variety of acronyms to describe particular experiments or applications. New applications, with new audiences, bring new technical jargon.

Product Resources - MS

LC?MS software

In addition to expressing his longing for a Star Trek "tricoder," columnist Ken Busch shows that the core processes of ionization, ion dissociation, and mass determination in mass spectrometry are all completed in very short times compared to the overall length of the analysis.

Product Resources - Molecular

Product Resources - Atomic

This month's "Focus on Quality" presents a critique of the GAMP Good Practice Guide. And while columnist Bob McDowall finds much to recommend in the guide, he finds much more cause for concern.

Here the author compares near-infrared to mid-infrared as analytical tool in process management. he weighs the pros and cons of both spectral regions and suggests general applications for which one or the other is better suited.

Acid stills

Mass spectrometer

Imaging spectrograph

Realistically, 2005 was a good year for the laboratory analytical and life science instrument industry. Although growth has moderated from that experienced in the 1990s, a general rebound in worldwide industrial demand, and continued spending for life science and strong growth in Asia and North America drove instrument systems and aftermarket sales. Similar to last year, 2006 should be a year of healthy sales growth as global economic conditions support continued market expansion.

The Shamrock 163i imaging spectrograph from Andor Technology is based on a Czerny-Turner optical layout featuring a focal length of 163 mm, an entrance aperture ratio of f/3.6, and a wavelength resolution of 0.17 nm. The instrument includes interchangeable gratings and slits that allow users to select different wavelength ranges and resolutions. Andor Technology, Belfast, UK; www.andor.com

Tunable diode laser absorption spectroscopy (TDLAS) has evolved from a laboratory specialty technique to the foundation for highly sensitive and specific gas-phase sensors for the process environment. This article discusses two recently developed products, a portable trace gas monitor, and a water vapor flow sensor.

Getting light from one place to another is a key task in any spectroscopic method. Sometimes we send light through (mostly) empty space using mirrors or lenses, and sometimes we use things called fiber optics. This installment of "The Baseline" tackles fiber optics.

This year's survey of salaries and job attitudes reveals that the market seems stable, but many spectroscopists are feeling the pressure of the economy at work.

IR imaging provides a new tool for disease detection, revealing compositional and structural information in tissue previously not available with contrast staining.

Part IV of this four-part series wraps up the discussion of mass calibration, covering the "new generation" attributes that have become apparent as researchers aim to meet the calibration demands of proteomics.

The concentration dependent influence of Na+ and K+ions on mass spectra of peptides is shown with human gastrin as a model peptide. With electrospray ionization the doubly charged protonated molecule ion [M+2H]2+ is normally the preferred ionization product. However, trace amounts of alkali metal ions already form clusters (adducts) with the peptide molecule, such as [M+H+Na]2+, which become dominating at higher concentrations. With Na+/K+ concentrations below 0.1 mg/kg (ppm) only a few clusters appear, which allow the correct doubly charged molecule ion to be assigned for a subsequent MS–MS experiment. With concentrations of 10 ppm and higher the alkali clusters become the most abundant peaks in the spectrum, and the absolute sensitivity is decreased by a factor of 5–10. Experiments were performed with water and water–methanol mixtures with a known Na+/K+ +content.

Many important biological signals are triggered by the binding of a peptide hormone to its cognate receptor at the cell surface. Using stopped-flow fluorescence spectroscopy, the authors have been able to observe, in real time, ligand binding to epidermal growth factor receptors expressed at the surface of intact cells. This method allows for the measurement of kinetic association and dissociation rates with high data density in a native cellular environment, providing insights into the signal-initiation process in this system that have not been revealed through the determination of ligand-binding constants obtained by more traditional methods.