Spectrometry simultaneous monitoring ions

Electro-Optical Ion Detectors in Mass Spectrometry Simultaneous Monitoring of All Ions over Wide Mass Ranges... 

Rodgers, R. P., White, F. M., Hendrickson. C. L Marshall. A. G. und Andersen, K. V., Resolution, elemental composition, and simultaneous monitoring by Fourier transform ion cyclotron resonance mass spectrometry of organosulfur species before and after diesel fuel processing. Anal. Chem. 1998, 70, 4743-4750. 

The plasma samples were purified on an anion exchange resin MCI GEL CA08P (170 X 10 mm. Cl ). DL-Pantothenic acid and DL-hopantenic acid were eluted with 1 M NaCl solution and free acids were extracted with ethyl acetate from the eluate acidified with 6 M HCl in the presence of ammonium sulfate and esterified with 1.5 M HCl in methanol at room temperature for 1 h. The resulting methyl esters were trifluoroacetylated with trifluoroacetic anhydride in dichloro-methane at room temperature for 30 min and analyzed by GC-MF. Mass spectrometry with selected-ion monitoring was employed for the simultaneous determination of the enantiomers of pantothenic acid and hopanthenic acid. The stable mass fragments were detected at m/z 257 and 271, being the base peaks of pantothenic acid and hopantenic acid, respectively (Fig. 31). 

Van Thuyne, W., Van Eenoo, R, and Delbeke, F.T. (2008) Implementation of gas chromatography combined with simultaneously selected ion monitoring and full scan mass spectrometry in doping analysis. Journal of Chromatography A, 1210,193-202. 

The most suitable and effective method to date that is capable of analyzing several neurosteroids simultaneously is gas chromatography/electron capture-negative chemical ionization/mass spectrometry (GC/EC-NCI/MS) with selected ion monitoring (SIM). This technique allows a focus on a few specific ions bearing structural information. 

They are still the workhorses of coupled mass spectrometric applications, as they are relatively simple to run and service, relatively inexpensive (for a mass spectrometer), and provide unit mass resolution and scanning speeds up to approximately 10,000 amu/s. This even allows for simultaneous scan/ selected ion monitoring (SIM) operation, in which one part of the data acquisition time is used to scan an entire spectrum, whereas the other part is used to record the intensities of selected ions, thus providing both qualitative information and sensitive quantitation. They are thus suitable for many GC-MS and liquid chromatography-mass spectrometry (LC-MS) applications. In contrast to GC-MS with electron impact (El) ionization, however, LC-MS provides only limited structural information as a consequence of the soft ionization techniques commonly used with LC-MS instruments [electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI)]. Because of this limitation, other types of mass spectrometers are increasingly gaining in importance for LC-MS. 

Gregov, M., Ojanpera, I., Vuori, E. Simultaneous screening for 238 dmgs in blood by liquid chromatography-ion spray tandem mass spectrometry with multiple-reaction monitoring. J. Chromatogr. B Analyt. Technol. Biomed. Life Sci. 795, 41-53 (2003)... 

IRMS LC MDGC MS MSA NIF NMR OAV OSV PCA RAS RP SDE SFE SIM SNIF SPME TIC TLC Stable Isotope Ratio Mass Spectrometry Liquid Chromatography MultiDimensional Gas Chromatography Mass Spectrometry Multivariate Sensory Analysis Nasal Impact Frequency Nuclear Magnetic Resonance spectroscopy Odor Activity value Odor Spectrum Value Principal Component Analysis Retronasal Stimulation Reversed Phase Simultaneous steam Distillation Extraction Supercritical Fluid Extraction Selected Ion Monitoring Surface of Nasal Impact Frequency Solid Phase Micro Extraction Total Ion Current Thin Layer Chromatography... 

Liquid chromatography, coupled with mass spectrometry and tandem mass spectrometry (LC-MS/MS), is a universal technique for determining toxins in food. The first multiple reaction monitoring (MRM) method for polyether marine toxins was used for the determination of DSP toxins and this technique has been successfully applied to the simultaneous determination of various groups of polyether toxins in shellfish (Draisci et al., 1998, 1999). MRM involves the selection of a precursor ion and its product ion from CID fragmentations and it is highly selective. For azaspiracids, the first validated LC-MS/MS method was developed for the determination of AZAl... 

The application of GC for the introduction of complex samples into field asymmetric IMS (FAIMS) and differential mobility spectrometry (DMS) instruments is also used extensively. Fast capillary chromatography in which relatively simple mixtures can be separated in less than a second provides a rapid separation-and-introduction method for DMS. One specific advantage of FAIMS (or DMS) as a chromatographic detector is that both positive and negative ions can be monitored simultaneously from the GC effluent. Figure 3.10 provides a schematic of a typical capillary GC/DMS instrument in which SPME is used to inject semivolatile compounds into the capillary column with DMS detection. 

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