ESI coupling

The qualitative determination of anionic surfactants in environmental samples such as water extracts by flow injection analysis coupled with MS (FIA-MS) applying a screening approach in the negative ionisation mode sometimes may be very effective. Using atmospheric pressure chemical ionisation (APCI) and electrospray ionisation (ESI), coupled with FIA or LC in combination with MS, anionic surfactants are either predominantly or sometimes exclusively ionised in the negative mode. Therefore, overview spectra obtained by FIA—MS(—) often are very clear and free from disturbing matrix components that are ionisable only in the positive mode. However, the advantage of clear... 

There are several types of ionization sources [MALDI, ESI, FAB (fast atom bombardment), PD (Cf-252 plasma desorption), El (electron ionization), Cl (chemical ionization) etc.], different types of mass analyzers [combinations of magnetic and electric sectors, quadrupolar filters (Q) and ion traps (IT), time-of-flight (TOF) and FT-ICR] and different detectors, each with its own advantages and drawbacks. We describe herein only the systems that presently have widespread use for the study of biomolecules ESI coupled to a quadrupole (or triple quadrupole, QqQ) mass analyzer or an ion trap, the MALDI source with the linear or reflectron TOF analyzer, and the FT-ICR system which can be equipped with both ESI and MALDI sources. 

The couphng of ion-exchange (lEC) and ion-pairing chromatography using ESI coupled with MS/MS allowed the determination of several environmentally important organoarsenic compounds in complex mixtures. An arsenobetaine could be confirmed by MS/MS after lEC [428]. Arsenc species were determined by ESI-LC-MS applying post column methanol addition [441]. 

ESI, coupled with low-energy CID, although structurally less informative, can provide important structure-related data for polyunsaturated fatty acids [10] and polyhydroxy unsaturated fatty acids [11]. Fragmentation is directed by the position of the hydroxy group or a double bond. As a consequence, isomer-specific CID spectra are produced. 

The successful on-line interfacing of several ion sources has made them dominant players in quantitative analyses using mass spectrometry. These include electron ionization (El) and chemical ionization (Cl) both coupled to GC, and the atmospheric pressure ionization (API) methods of atmospheric pressure chemical ionization (APCI) atmospheric pressure photoionization (APPI), and electrospray ionization (ESI) coupled to LC. In addition, matrix assisted laser desorption ionization (MALDI) is seeing increased application in off-line LC/MS applications. 

The increasing use of mass spectrometry (MS) in polymer characterization is attributed to the development of ionization techniques such as MALDI and ESI coupled with innovations in mass analyzers such as reflectron-TOF and FT-ICR. This has greatly augmented the capabilities of MS to better understand the detailed composition of polymeric materials. Furthermore, increased mass resolution and accuracy coupled to hyphenated techniques permits greater detail about even minor components in polymeric biomaterials to be assessed, especially with regard to composition of repeat and end groups. In this book Maziarz and coworkers (10) review the application of mass spectrometiy in characterization of polymeric biomaterials. 

Applications of MALDI and ESI Coupled to QMF, QIT, LQIT, and Hybrid Mass Spectrometers... 

APPLICATIONS OF MALDI AND ESI COUPLED TO QMF, QIT, LQIT, AND HYBRID MASS SPECTROMETERS... 

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