ICP-MS

May 01, 2008
Special Issues
In drug discovery, determining information about the extent of metabolism and the elucidation of metabolite structures is a vital step for lead optimization and drug scaffold refinement. The identification and characterization of metabolites plays an important role in both the drug discovery and development phases, as unsuitable pharmacokinetics (bioavailability and drug distribution), toxicity, and adverse drug reactions might be linked to metabolic instability. Historically, metabolite identification was carried out after a compound had been chosen for drug development. However, to reduce candidate failures attributed to toxicity effects, many pharmaceutical companies now conduct these experiments in the earliest phases of candidate drug selection.
May 01, 2008
Special Issues
With electron ionization (EI) used in most gas chromatography–mass spectrometry (GC–MS) applications, the molecular ion typically is broken apart into multiple fragment ions during the EI process.
May 01, 2008
Spectroscopy
By Spectroscopy Editors
While inductively coupled plasma-mass spectrometry (ICP-MS) is capable of part-per-quadrillion (ppq) detection limits under ideal conditions, most applications do not require this level of sensitivity and do not justify the cost associated with achieving it. Practical sensitivity in ICP-MS is determined not by instrument signal-to-noise ratio, but rather by controlling interferences and matrix effects in real samples. Understanding the sources of these effects and their management is critical in determining the most practical way to achieve specific data quality objectives.
Apr 01, 2008
Spectroscopy
By Spectroscopy Editors
Speciation analysis has grown rapidly and has expanded to a variety of markets, including environmental, clinical, food, nutraceutical, and bioanalytical. This growth has resulted from the realization that knowing the total amount of an element does not always provide adequate information for assessing health and environmental effects, but knowing which form of the element is present presents a much more comprehensive picture.
Mar 01, 2008
Application Notebook
Mar 01, 2008
Special Issues
Although not currently used in U.S. or European aquaculture, malachite green (MG) is still an effective and inexpensive fungicide that is used in other countries, particularly in Asia. During metabolism, MG reduces to leucomalachite green (LMG) (Figure 1), which has been shown to accumulate in fatty fish tissues. Trace levels of MG and LMG residues continue to be found in fish products. In a 2005 report, MG was found in 18 out of 27 live eel or eel products imported from China to Hong Kong local market and food outlets, resulting in a government recall and destruction of all remaining products (1).
Mar 01, 2008
Special Issues
By Spectroscopy Editors
Because it is extremely rapid, biomarker discovery and identification using liquid chromatography–mass spectrometry (LC-MS), including both ion-trap and triple-quadrupole LC–MS, is well established. Fractionation of complex samples before LC–MS-MS analysis might be necessary to identify the proteins, greatly increasing the number of analyses required. In this case, there is ongoing debate regarding knowing whether the protein is identified correctly, knowing how much prior fractionation is needed to reduce complexity to the point where low-abundance proteins can be detected reliably, and balancing specificity with sensitivity.
Mar 01, 2008
Special Issues
The usefulness of liquid chromatography–mass spectrometry–mass spectrometry (LC–MS-MS) methods for the unambiguous identification and quantification of pesticides in complex matrix samples is well known. Triple-quadrupole systems have proven to be useful for this task because of their high specificity in MS-MS mode and their low detection limits. However, working in MS-MS mode makes any MS system blind to other compounds of interest.
Mar 01, 2008
Special Issues
By Spectroscopy Editors
The nanoLC LIT-TOF approach combines multiple capabilities that improve the ability to characterize complex protein mixtures significantly.
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