Mass spectrometers electrospray ionization

Figure 5 Examples of Data Generated on an Electrospray Ionization Mass Spectrometer, (a) Proteins Typically Produce Positive, Multiply Charged Ions and (b) Oligonucleotides Generate Negative, Multiply Charged Ions. Inset are the Computer-Generated Molecular Weight Spectra...

Figure 4. Electrospray of the LO active site peptide (sample 1). The electrospray ionization mass spectrometer was scanned in noncontinuum mode over a range of m/z of 350 to 2000 at 5 s/scan (see text for details).

Soft ionization methods produce few fragments under relatively mild conditions. The ionization method that has received the most attention in terms of its applicability to protein and DNA analysis is the electrospray ionization (ES) technique. This is a soft method that is capable of generating molecular ions from biological macromolecules present in solution. Table 12.3 gives examples of the charge and m/z ranges that have been observed with some biopolymer species in electrospray ionization mass spectrometers. 

Fig. 14 Schematic representation of a capillary electrophoresis instrumentation coupled in tandem through an interface to an electrospray ionization mass spectrometer. A microchamber affinity device containing an immobilized C-18 or antibody to a porous bead is located near the inlet of the capillary. (Modified from Ref. 441.)...

The Coupling of Microfabricated Fluidic Devices with Electrospray Ionization Mass Spectrometers... 

The reaction of sodium azide with aryldiazonium salts yields arylpentazoles (equation 14.49), from which it has been possible to generate the cychc anion psig] through molecular fragmentation in an electrospray ionization mass spectrometer. ... 

Figure 35.12 shows a schematic diagram of an online high-throughput detection system for a reaction product synthesized by a microreactor. The system has a synthesis chip that a microreactor for the synthesis of 2,2,2-trifluore-A-phenetyl acetamide (TPA), an extraction chip for the purification of TPA from the reaction mixture, and an electrospray ionization mass spectrometer (ESl-MS) for... 

The recent progress in micro/nanofabrication technology as well as microfluidics has spurred efforts to interface chip-based separation devices with electrospray ionization mass spectrometers. As frontiers in the ability to miniaturize the mass analyzers are being extended further, an... 

In more recent work, Gu et al. have reported a geometry-independent neutral desorption device [57]. The instrument uses a neutral desorber gas which is directed onto the surface to remove the adsorbed analytes. A multistage extractive electrospray ionization mass spectrometer (EESI-MS) was used to successfully obtain spectra of traces of volatile explosives (i.e., TATP) and nonvolatile explosives, (i.e., 2,4,6-trinitrotoluene [TNT], 1,3,5-trinitroperhydro-l, 3,5-triazine [RDX], and octahydro-13,5,7-tetranitro-1,3,5,7-tetrazocine [HMX] from a series of surfaces, including wet and oily skin). Samples in the subpico-gram level were detected. 

FIGURE 1 Diagram of the capillary HPLC configuration as attached to the electrospray ionization mass spectrometer. Flow through the 320- m-i.d. packed capillary columns is adjusted to 4 1 per minute. 

Lubben, A.T., Mclndoe, J.S., and Weller, A.S. (2008) Coupling an electrospray ionization mass spectrometer with a glovebox a straightforward, powerful, and convenient combination for analysis of air-sensitive organometallics. Organometallics, 27, 3303-3306. 

Smaller internal diameters give more concentrated bands (less dilution). If there is a limitation on the available amount of sample, smaller ID columns wUl improve the detection limit with concentration-sensitive detectors. Typical concentration-sensitive detectors are UV, fluorescence, and electrospray ionization mass spectrometers (ESI-MSs). 

Carroll DI, Dzidic I, Horning EC and Stillwell RN (1981) Atmospheric pressure ionization mass spectrometry. Applied Spectroscopic Review 17 337-406. Chowdhury SK, Katta V and Chait BT (1990) An electrospray-ionization mass spectrometer with new features. Rapid Communications of Mass Spectrometry 4 81-87. 

K Gartenmann, S Kochhar. Short-chain peptide analysis by high-performance liquid chromatography coupled to electrospray ionization mass spectrometer after derivatization with 9-fluorenylmethyl chloroformate. J Agric Food Chem 47 5068-5071, 1999. 

Figure 4.4 LC-ICP-MS analysis of alkyl phosphonic acids in food and beverage matrices [24]. Reprinted from Kubachka, K.M., Richardson, D.D., Heitkemper, D.T., Caruso, J.A., Detection of chemical warfare agent degradation products in foods using liquid chromatography coupled to inductively coupled plasma mass spectrometry and electrospray ionization mass spectrometer. Journal of Chromatography A, 2008, 1202, (2), 124-131, with permission from Elsevier...

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