Mass spectrometry, Electrospray ionisation

A series of aliphatic polyesters, characterised by asymmetric oligomer distributions, heteroterminated linear chains, and cyclic oligomers, were studied using MALDI. Structural characterisation results were compared with those from fast atom bombardment mass spectrometry, electrospray ionisation mass spectrometry, NMR and end-group titration. MALDI molecular weight determination was contrasted with those from GPC and NMR. 23 refs. 

For off-bead analysis, coupling between chromatographic separation and mass spectrometric detection has proven especially powerful. The combination between high performance liquid chromatography (HPLC) and electrospray ionisation mass spectrometry has the advantage that purity of product mixtures can be coupled on-line with the product identification. 

Kasprzyk-Hordern B, Dlnsdale RM, Guwy AJ (2007) Multi-residue method for the determination of basic/neutral pharmaceuticals and illicit dmgs in surface water by solid-phase extraction and ultra performance liquid chromatography-positive electrospray ionisation tandem mass spectrometry. J Chromatogr A 1161 132-145... 

Hvattum, E., Determination of phenolic compounds in rose hip (Rosa canina) using liquid chromatography coupled to electrospray ionisation tandem mass spectrometry and diode-array detection, Rapid Commun. Mass Spectrom., 16, 655, 2002. 

Fast atom bombardment (FAB) Plasma desorption (PD) Liquid secondary-ion mass spectrometry (LSIMS) Thermospray (TSP)/plasmaspray (PSP) Electrohydrodynamic ionisation (EHI) Multiphoton ionisation (MPI) Atmospheric pressure chemical ionisation (APCI) Electrospray ionisation (ESI) Ion spray (ISP) Matrix-assisted laser desorption/ionisation (MALDI) Atmospheric pressure photoionisation (APPI) Triple quadrupole (QQQ) Four sector (EBEB) Hybrid (EBQQ) Hybrid (EB-ToF, Q-ToF) Tandem ToF-ToF Photomultiplier... 

The mass spectra of mixtures are often too complex to be interpreted unambiguously, thus favouring the separation of the components of mixtures before examination by mass spectrometry. Nevertheless, direct polymer/additive mixture analysis has been reported [22,23], which is greatly aided by tandem MS. Coupling of mass spectrometry and a flowing liquid stream involves vaporisation and solvent stripping before introduction of the solute into an ion source for gas-phase ionisation (Section 1.33.2). Widespread LC-MS interfaces are thermospray (TSP), continuous-flow fast atom bombardment (CF-FAB), electrospray (ESP), etc. Also, supercritical fluids have been linked to mass spectrometry (SFE-MS, SFC-MS). A mass spectrometer may have more than one inlet (total inlet systems). 

Electron impact ionisation (El) stands for extensive fragmentation, but also produces molecular ions. The other ionisation methods shown in Table 6.10 mainly generate quasi-molecular ions for various compound classes. Protonation of organic compounds is one of the most fundamental processes of Cl, FAB and ESI mass spectrometry. Apart from electrospray (ESI), which... 

Crawford, E., Dyson, P., Forest, O., Kwok, S. Mclndoe, J. S. Energy-dependent Electrospray Ionisation Mass Spectrometry of Carbonyl Clusters. 

Jahnke, A., Gandrass, J., Ruck, W. (2004). Simultaneous determination of alkylphenol ethoxylates and their biotransformation products by liquid chromatography/electrospray ionisation tandem mass spectrometry. J. Chromatogr. A 1035(1), 115-122. 

Giguere and Mayer [121] reported on the dissociation of gas-phase poly(vinyl acetate) (PVAc), see Figure 21, ionised by Li+ investigated by electrospray-ionisation (ESI) mass and collision induced dissociation (CID) mass spectrometry. 

Stintzing F C, Schieber A and Carle R (2002), Identification of betalains from yellow beet (Beta vulgaris L.) and cactus pear (Opuntia ficus-indica (L.) Mill.) by high-performance liquid chromatography - electrospray ionisation mass spectrometry , J Agric Food Chem, 50, 2302-2307. 

In the present chapter, we first provide some general information concerning the chemistry of waxes and lipids currently encountered in various items from our cultural heritage and we detail the main protocols based on direct mass spectrometry that have been developed so far. We then discuss the mass spectra obtained by EI-MS on a range of reference substances and materials sampled from museum and archaeological artefacts. We then focus on the recent possibilities supplied by electrospray ionisation for the elucidation of the structure of biomarkers of beeswax and animal fats. 

Figure 4.1 Analytical strategy in which direct mass spectrometry analyses using either elec tron ionisation or electrospray are used for detecting and identifying lipid substances in archaeological and museum samples...

The type of proteinaceous binder was correctly identified in all model samples. In only one case (S10), the animal glue was additionally identified, although the restorer who prepared these model samples declared that the sample contained only egg binder. It is possible that this sample was contaminated during its preparation or during laboratory treatment. The results indicate that this method does not allow reliable identification of the presence of individual egg yolk and egg white most probably it is caused by the presence of a trace of egg white that is always present in the egg yolk preparations (and vice versa) and can be detected by the highly sensitive PMM method. The identification of individual types of animal glues will never be reliable by MALDI-TOF mass spectrometry because of their similar composition the application of ESI (electrospray ionisation)-MS/MS (Section 6.5) could possibly overcome this problem. Only the fish glue, whose peptide... 

Vallejo F, Tomas-Barberan FA and Ferreres F. 2004. Characterisation of flavonols in broccoli (Brassica oleracea L. var. italica) by liquid chromatography-UV diode-array detection-electrospray ionisation mass spectrometry. J Chromatogr A 1054(1—2) 181—193. 

Amao MB, Cano A, Alcolea JF and Acosta M. 2001b. Identification of hydrolysable tannins in the reaction zone of Eucalyptus nitens wood by high performance liquid chromatography-electrospray ionisation mass spectrometry. Phytochem Anal 12(2) 120—127. 

In common with M. macedonicus, urine from male M. spretus also demonstrated a MUP-sized band following gel electrophoresis. The proteins within this band were analysed by high resolution anion exchange chromatography and electrospray ionisation mass spectrometry (ESI-MS). The former technique produced an elution profile consisting of just three peaks, in contrast to both the more complex patterns observed previously from M. m. domesticus and the single major peak in M. macedonicus. Furthermore, similar analyses from five individual males resulted in near... 

Several years later, the next step in the application of MS-MS for mixture analysis was developed by Hunt et al. [3-5] who described a master scheme for the direct analysis of organic compounds in environmental samples using soft chemical ionisation (Cl) to perform product, parent and neutral loss MS-MS experiments for identification [6,7]. The breakthrough in LC-MS was the development of soft ionisation techniques, e.g. desorption ionisation (continuous flow-fast atom bombardment (CF-FAB), secondary ion mass spectrometry (SIMS) or laser desorption (LD)), and nebulisation ionisation techniques such as thermospray ionisation (TSI), and atmospheric pressure ionisation (API) techniques such as atmospheric pressure chemical ionisation (APCI), and electrospray ionisation (ESI). 

T. Covey, Biochemical and Biotechnological Applications of Electrospray Ionisation Mass Spectrometry, In A.P. Synder (Ed.), ACS Symposium Series 619, ACS, Washington, DC, 1996, pp. 21—59. 

Owing to the anionic character of LAS, an electrospray ionisation (ESI) interface operated in negative ion mode is particularly attractive for the mass spectrometric detection of this surfactant type. Consequently, a great part of the atmospheric pressure ionisation-mass spectrometry (API-MS) work on LAS is devoted to the application of (— )-ESI-MS. 

For quantitative analysis of organic compounds in general by means of liquid chromatography-electrospray ionisation mass spectrometry (LC-ESI-MS), one should be aware of two major factors, which may strongly impact on the outcomes. These are directly associated with the process of ion generation in the interface. 

Li, L., Tsao, R., Dou, J., Song, F., Liu, Z., and Liu, S. (2005). Detection of saponins in extract of Panax notoginseng by liquid chromatography-electrospray ionisation-mass spectrometry. Anal. Chim. Acta 536,21-28. 

Pihlainen, K. and Kostiainen, R., Effect of the eluent on enantiomer separation of controlled drugs by liquid chromatography-ultraviolet absorbance detection-electrospray ionisation tandem mass spectrometry using vancomycin and native fi-cyclodextrin chiral stationary phases, J. Chromatogr. A, 1033, 91, 2004. 

Vassort, A., Barrett, D. A., Shaw, P. N., Ferguson, P. D., and Szucs, R. (2005). A generic approach to the impurity profiling of drugs using standardised and independent capillary zone electrophoresis methods coupled to electrospray ionisation mass spectrometry. Electrophoresis 26, 1712—1723. 

Dahlmann, J., Budakowski, W.R. and Luckas, B., Liquid chromatography-electrospray ionisation-mass spectrometry based method for the simultaneous determination of algal and cyanobacterial toxins in phytoplankton from marine waters and lakes followed by tentative structural elucidation of microcystins, /. Chromatogr., 994, 1-2, 45, 2003. 

Hartig C, Storm T, Jekel M (1999). Detection and identification of sulphonamide drugs in municipal wastewater by liquid chromatography coupled with electrospray ionisation tandem mass spectrometry. J Chromatography A 854 163-173 Hayes HM, Tarone RE, Cantor KP (1995) On the association between canine mahgnant lymphoma and opportunity for exposure to 2,4-dichlorophenoxyacetic acid. Environ Res 70 119-125... 

Aguilar, C., Hofte, A.J., Tjaden, U.R. and van der Greef, J. (2001) Analysis of histones by on-line capillary zone electrophoresis-electrospray ionisation mass spectrometry. Journal of Chromatography. A, 926, 57-67. 

---