Electrospray mass spectrometry (ESI‐MS) in the study of metal–ligand solution equilibria

Abstract

In the 20 years, since the introduction of electrospray mass spectrometry (ESI-MS), the use of this technique in various fields of inorganic, organometallic, and analytical chemistry has been steadily increasing. In this study, the application of ESI-MS to the study of metal-ligand solution equilibria is reviewed (till 2004 included). In a first section, advantages and drawbacks of ESI-MS in this type of application are described. Subsequently, a list of ca. 300 studies is reported, in which ESI-MS was used to give number and stoichiometry of the species at equilibrium, or also to estimate their stability constants. All studies are classified according to the metal ions under examination. Other related applications, such as host-guest interactions and metal ion-protein binding studies, are briefly reviewed as well.

Fe- and Cu-Complex Formation with Artificial Ligands Investigated by Ultra-High Resolution Fourier-Transform ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS): Implications for Natural Metal-Organic Complex Studies

“…The advantage of ESI-MS resides in its easy application-samples in solution can be swiftly processed under a wide array of conditions-and its soft ionization procedure which allows for the detection of whole metal-organic compounds (Di Marco and Bombi, 2006). The ESI-MS measurements of known metal-ligand mixtures can be compared with speciation data acquired from other methods such as computational speciation modeling, crystallography, or complex affinity titrations.…”

“…To complement CLE-ACSV by ESI-MS and ESI-FT-ICR-MS, potential instrument-specific artifacts of the ESI-MS technique have to be taken into account (Di Marco and Bombi, 2006;Keith-Roach, 2010;Waska et al, 2015). Examples for such effects are:…”

Exploring metallodrug–protein interactions by mass spectrometry: comparisons between platinum coordination complexes and an organometallic ruthenium compound

“…However, the optimisation and the standardisation of experimental ESI MS procedures directed to metallodrugs require attention, since the variability in the ESI MS response depends on many factors, such as the nature of the protein, the nature of the metal/ligands/charge and the specific solution conditions (pH, buffer, etc.) [27,28].…”

Development of the application of speciation in chemistry

“…This very rapidly developing area of analytical chemistry has also influenced speciation studies, where it can be used to identify the compositions of the species formed in solution [64]. This method is appropriate for application to inert systems, but it is destructive and can disrupt any equilibrium or speciation in labile systems.…”

“…Cu transport in the blood has been studied extensively [219,220], where 64 Cu isotope experiments have shown that most of the Cu bound to ceruloplasmin is not exchangeable, whereas that bound to HSA is exchangeable with LMM Cu carriers, such as AAs. The resulting complexes formed with AAs are considered important as Cu carriers through membranes (Eq.…”