ICP-MS

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
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
The nanoLC LIT-TOF approach combines multiple capabilities that improve the ability to characterize complex protein mixtures significantly.
Mar 01, 2008
Special Issues
Beta-blockers are basic compounds that contain a secondary amino group in their structure. The amino substituents are typically an isopropyl group and a larger chain with a hydroxyl group in the beta position from the nitrogen atom (Table I). The simultaneous analysis of ?-blockers in biological samples is meaningful, and is made possible by the similarities in their structure. Gas chromatography (GC)–mass spectrometry (MS) has been the most used technique for their identification and quantification (4–6). However, most ?-blockers are nonvolatile and thus require derivatization via a cumbersome and time-consuming process before GC–MS analysis. In recent years, liquid chromatography (LC) coupled with mass spectrometric detection has evolved as the method of choice for drug analysis in the pharmaceutical, clinical, and forensic toxicology areas (4–8). In contrast to GC–MS, LC–MS-MS generally does not require derivatization and offers superior sensitivity. Moreover, due to the high specificity offered by LC–MS-MS, baseline chromatographic resolution often is not required, allowing for fast analysis in high-throughput environments.
Mar 01, 2008
Special Issues
Gas chromatography and comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC–TOFMS and GCxGC–TOFMS) were utilized to develop trace-level calibration curves in brewed green tea spiked with organochlorine and organophosphorus pesticide standards. A sensitive and robust calibration curve was developed from 10 to 500 parts per trillion (ppt), which allowed quantitative results to be determined for organochlorine–organophosphorus pesticides in brewed green tea. Exceptional limits of detection were achieved by GC–TOFMS and GCxGC–TOFMS at or below 10 ppt (solution concentration) for all but one of the pesticides. Stir bar sorption extraction (SBSE) was utilized to isolate the pesticide components from brewed green tea samples prior to analysis by GC–TOFMS and GCxGC–TOFMS. Different types of green tea were analyzed qualitatively by SBSE and GC–TOFMS with subsequent quantification for organochlorine–organophosphorus..
Feb 01, 2008
Spectroscopy
The implementation of ICP-MS as a detection system for reversed-phase HPLC was proven to be a useful technique for the investigation of pharmaceutical molecules containing the heteroatoms sulfur, phosphorus, bromine, and chlorine, as well as organometallic compounds containing a transition metal such as cobalt.
Jan 01, 2008
Spectroscopy
In this month's installment, columnist Ken Busch addresses the molecular applications of inductively coupled plasma linked with mass spectrometry (ICP-MS), and how those applications have developed.
Jan 01, 2008
Spectroscopy
By Spectroscopy Editors
Inductively coupled plasma (ICP) spectroscopy is an important optical emission technique, with strong applications in environmental testing and related areas. The basic principle of ICP involves the introduction of a liquid sample into an argon plasma torch, which provides the excitation energy required to stimulate atomic emission in the sample. The geometry of the torch with respect to the optical components provides one source of control over the analysis. The axial mode, with the optics directed toward the plasma jet, provides better detection levels, although the radial (side-on) mode generally is less problematic.
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