Tandem ion-trap

The resulting microdialysate samples were mixed (9 1) with acetyl-(3-methylcholine (internal standard, lng/pL), and a 950 pL portion was analyzed on a Discovery Cig column (50 cm x 2.1 mm i.d.). The method used 20 mM ammonium acetate/20mM heptafluorobutyric acid in methanol/water (1 9, pH 3.2) as the mobile phase at 0.4mL/min, and the analyte and internal standard were detected by tandem ion-trap mass spectrometry. The calibration graph was linear up to 500fg/pL of acetylcholine, and the on-column detection limit was 200 fg acetylcholine. 

Heller DN, Ngoh MA, Electrospray ionization and tandem ion trap mass spectrometry for the confirmation of seven beta-lactam antibiotics in bovine milk. Rapid Commun. Mass Spectrom. 1998 12(24) 2031-2040. 

Cao, I, Yin, C., Qin, Y., Cheng, Z., Chen, D. Approach to the study of flavone di-C-glycosides by high performance liquid chromatography-tandem ion trap mass spectrometry and its application to characterization of flavonoid composition in Viola yedoensis. J. Mass Spectrom. 49(10), 1010-1024 (2014)... 

Another approach to mass analysis is based on stable ion trajectories in quadnipole fields. The two most prominent members of this family of mass spectrometers are the quadnipole mass filter and the quadnipole ion trap. Quadnipole mass filters are one of the most connnon mass spectrometers, being extensively used as detectors in analytical instnunents, especially gas clnomatographs. The quadnipole ion trap (which also goes by the name quadnipole ion store, QUISTOR , Paul trap, or just ion trap) is fairly new to the physical chemistry laboratory. Its early development was due to its use as an inexpensive alternative to tandem magnetic sector and quadnipole filter instnunents for analytical analysis. It has, however, staned to be used more in die chemical physics and physical chemistry domains, and so it will be described in some detail in this section. 

One of the prineiple uses of the ion trap is as a tandem-in-time mass speetrometer. Ions with a partieular m/z ratio fomied in the ion trap, or mjeeted into the trap from an external soiiree, ean be isolated by resonantly ejeeting all other... 

A. J. H. Eouter, J. van Door-nmalen, J. J. Vreuls and U. A. Th Brinkman, On-line solid-phase extr-action-thermal desorption-gas chr-omatography with ion trap detection tandem mass spectr-ometr-y for the analysis of microcontaminants in water , 7. High Resolut. Chromatogr. 19 679-685(1996). 

Tandem quadrupole and magnetic-sector mass spectrometers as well as FT-ICR and ion trap instruments have been employed in MS/MS experiments involving precursor/product/neutral relationships. Fragmentation can be the result of a metastable decomposition or collision-induced dissociation (CID). The purpose of this type of instrumentation is to identify, qualitatively or quantitatively, specific compounds contained in complex mixtures. This method provides high sensitivity and high specificity. The instrumentation commonly applied in GC/MS is discussed under the MS/MS Instrumentation heading, which appears earlier in this chapter. 

Tandem mass spectrometry (MS/MS) is a method for obtaining sequence and structural information by measurement of the mass-to-charge ratios of ionized molecules before and after dissociation reactions within a mass spectrometer which consists essentially of two mass spectrometers in tandem. In the first step, precursor ions are selected for further fragmentation by energy impact and interaction with a collision gas. The generated product ions can be analyzed by a second scan step. MS/MS measurements of peptides can be performed using electrospray or matrix-assisted laser desorption/ionization in combination with triple quadruple, ion trap, quadrupole-TOF (time-of-flight), TOF-TOF or ion cyclotron resonance MS. Tandem... 

Tandem mass spectrometry (MS-MS) uses more than one mass analyzer for structural and sequencing studies that have been found very useful for anthocyanin characterization. These mass analyzers may be of the same type (triple or quadru-poie)85,86 Qj. such as ion trap quadrupole, - and quadrupole-time-of-flight... 

A further extension of the DFG S19 method was achieved when polar analytes and those unsuitable for GC were determined by LC/MS or more preferably by liquid chromatography/tandem mass spectrometry (LC/MS/MS). Triple-quadrupole MS/MS and ion trap MS" have become more affordable and acceptable in the recent past. These techniques provide multiple analyte methods by employing modes such as time segments, scan events or multiple injections. By improving the selectivity and sensitivity of detection after HPLC separation, the DFG S19 extraction and cleanup scheme can be applied to polar or high molecular weight analytes, and cleanup steps such as Si02 fractionation or even GPC become unnecessary. 

The most widely regarded approach to accomplish the determination of as many pesticides as possible in as few steps as possible is to use MS detection. MS is considered a universally selective detection method because MS detects all compounds independently of elemental composition and further separates the signal into mass spectral scans to provide a high degree of selectivity. Unlike GC with selective detectors, or even atomic emission detection (AED), GC/MS may provide acceptable confirmation of the identity of analytes without the need for further information. This reduces the need to re-inject a sample into a separate GC system (usually GC/MS) for pesticide confirmation. Through the use of selected ion monitoring (SIM), efficient ion-trap or quadrupole devices, and/or tandem mass spectrometry (MS/MS), modern GC/MS instruments provide LODs similar to or lower than those of selective detectors, depending on the analytes, methods, and detectors. 

Appropriate use of RF and DC voltages means that some ions can be selectively retained and product ions generated. Some of these ions can then be selected and their product ions generated. In this manner, a fragmentation chain can be established. The ion trap is a typical tandem-in-time mass spectrometer, in which precursor and product ions are created and analysed in the same physical space ionisation and ion analysis, on the other hand, take place at different times ( MS/MS in time )- The operation can be repeated several times, making it possible to perform MS11. Ion trap mass spectrometry thus consists of ... 

Despite the fact that the ion trap via tandem MS offers more extensive possibilities for identification than QMS, in practice it is not often applied, because routine interpretation of the spectra is often complex and time-consuming. 

Fox, A. Krahmer, M. Harrelson, D. Monitoring muramic acid in air (after alditol acetate derivatization) using a gas chromatography-ion trap tandem mass spectrometer. J. Microbiol. Meth. 1996, 27,129-138. 

Larsson, L. Saraf, A. Use of gas chromatography-ion trap tandem mass spectrometry for the detection and characterization of microorganisms in complex samples. Mol. Biotechnol. 1997,7,279-287. 

Different mass analysers can be combined with the electrospray ionization source to effect analysis. These include magnetic sector analysers, quadrupole filter (Q), quadrupole ion trap (QIT), time of flight (TOF), and more recently the Fourrier transform ion cyclotron resonance (FTICR) mass analysers. Tandem mass spectrometry can also be effected by combining one or more mass analysers in tandem, as in a triple quadrupole or a QTOF. The first analyzer is usually used as a mass filter to select parent ions that can be fragmented and analyzed by subsequent analysers. 

Figeys, D. Aebersold, R. High sensitivity identification of proteins by electrospray ionization tandem mass spectrometry inital comparison between an ion trap mass spectrometer and a triple quadrupole mass spectrometer. Electrophoresis 1997,18, 360-368. 

It should be pointed out that FAB, MALDI, and ESI can be used to provide ions for peptide mass maps or for microsequencing and that any kind of ion analyzer can support searches based only on molecular masses. Fragment or sequence ions are provided by instruments that can both select precursor ions and record their fragmentation. Such mass spectrometers include ion traps, Fourier transform ion cyclotron resonance, tandem quadrupole, tandem magnetic sector, several configurations of time-of-flight (TOF) analyzers, and hybrid systems such as quadrupole-TOF and ion trap-TOF analyzers. 

Warscheid, B. Jackson, K. Sutton, C. Fenselau, C. MALDI analysis of Bacilli in spore mixtures by applying a quadrupole ion trap time-of-fhght tandem mass spectrometer. Anal. Chem. 2003, 75, 5608-5617. 

Farre M, Perez S, Gajda-Schrantz K, Osorio V, Kantiani L, Ginebreda A, Barcelo D (2010) First determination of C60 and C70 fullerenes and N-methylfulleropyrrolidine C60 on the suspended material of wastewater effluents by liquid chromatography hybrid quadrupole linear ion trap tandem mass spectrometry. J Hydrol 383(l-2) 44-51... 

Matejicek D, Houserova P, Kuban V (2007) Combined isolation and purification procedures prior to the high-performance liquid chromatographic-ion-trap tandem mass spectrometric determination of estrogens and their conjugates in river sediments. J Chromatogr A 1171 (l-2) 80-89... 

Schley, C., Altmeyer, M.O., Swart, R., Muller, R., Huber, C.G. (2006). Proteome analysis of Myxococcus xanthus by off-line two-dimensional chromatographic separation using monolithic poly-(styrene-divinylbenzene) columns combined with ion-trap tandem mass spectrometry. J. Proteome Res. 5, 2760-2768. 

QqLIT-MS-MS Quadrupole linear ion trap tandem mass spectrometer... 

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