A review of recent trends in electrospray ionisation–mass spectrometry for the analysis of metal–organic ligand complexes

Identification of the tri-Al tricitrate complex in Plantago almogravensis by hydrophilic interaction LC with parallel ICP-MS and electrospray Orbitrap MS/MS detection

“…This result can be explained by the fact that the other minor complexes are eluting in less defined peaks because of a probably lower stability of these forms and higher interaction with chromatographic material. 8 The obtained HILIC-ICP-MS chromatogram indicates the approximate retention time of the detected Al-complex, however, because Al is a mono-isotopic element it is not possible to examine the mass spectra obtained by HILIC-ESI-MS for molecular ions containing metals with specific isotopic signatures, as is the case for nickel 13 and cadmium complexes 14 for instance. A multitude of molecular ions is typically observed for Al signals detected in the root sample exposed to 400 mM Al (C); and the 31 P signal detected in leaves and shoot samples exposed to 400 mM Al (D).…”

“…Because of the gentle transition from solution to the gas phase and the low collision energies, the dissociation of metal complexes is less likely and singly-charged species with high mass resolution are generally produced, yielding simple mass spectra that facilitate assignment. 8 The lack of an isotope to aid with localization of Al-bearing complexes in mass spectra can be circumvented by parallel detection with an elemental detection technique, such as inductively coupled plasma (ICP)-MS, which allows determining the retention times of Al-complexes and pinpointing the region of the MS chromatogram that should be examined. Biological samples are too complex for direct infusion or flow injection, so chromatographic separation prior to ESI-MS measurements is required.…”

Electrospray Ionization Mass Spectrometry for the Quantification of Inorganic Cations and Anions

“…400 μmol dm (16) 4 (13) 15 (19) 71 (9) 7 (19) 2500 (0.02) 6 (7) 110 (0.11) 360 (7) 100 (0. 4) 25 (6) 11 (3) 15 (33) 11 (150) 81 (28) 5 (1400) 31 (14) 6 (11) 10 (13) 37 (4) 93 (7) 21 (110) 16 (36) 10 (90) 25 (20) 3 (18) 9 (18) 59 (9) 7 (16) 29 (32) 33 (14) 4 (21) 57 (11) 13 (8) 10 (9) 3 (11) 10 (18) 17 (7 , or 2-hydroxy-1-(2-hydroxy-4-sulfo-1-naphthylazo)-3-naphthoic acid (NN) for only Ca 2+ , were performed for comparison purposes. The results are listed in Table 3.…”

Aluminium speciation and internal detoxification mechanisms in plants: where do we stand?

“…Because low collision energies are applied, the ionization process generally produces singly-charged species with high mass resolution, yielding simple mass spectra that facilitate assignment. 22 ESI-MS also provides information on the stoichiometry of complex formation making it perhaps one of the most powerful tools for metal complex analysis. Biological samples are too complex for direct infusion or flow injection, so chromatographic separation is needed under conditions that prevent dissociation.…”

“…21 The limited interaction between metal complexes and size-exclusion chromatography (SEC) resins allows the separation of Al complexes from matrix components that suppress ionization, while minimizing interactions that may cause complex dissociation. 22 However, metal adsorption to residual COOH and OH groups on chromatography resins can interfere in speciation studies and this must be taken into account. 21 The OA-Al complexes identified thus far are highly polar, so hydrophilic interaction chromatography (HILIC) is another useful method for the separation of Al complexes prior to ESI-MS.…”