z-logo
Premium
Fourier transform ion cyclotron resonance mass spectral characterization of metal‐humic binding
Author(s) -
Stenson Alexandra C.
Publication year - 2009
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.3889
Subject(s) - chemistry , humic acid , fourier transform ion cyclotron resonance , metal , metal ions in aqueous solution , mass spectrometry , ion , analytical chemistry (journal) , characterization (materials science) , inorganic chemistry , environmental chemistry , chromatography , organic chemistry , nanotechnology , fertilizer , materials science
The interaction between metals and naturally occurring humic substances and the thereby induced issues of bioavailability and hydrogeochemical turnover of metal ions in natural waters have been the subject of intense study for decades. Traditional bulk techniques to investigate metal‐humic binding (e.g. potentiometry and inductively coupled plasma mass spectrometry (ICP‐MS)) can provide quantitative results for the relative abundance and distribution of metal species in humic samples and/or overall binding constants. The shortcoming of these bulk techniques is the absence of structural detail. Ultra‐high‐resolution mass spectrometry, currently the only technique demonstrated to resolve individual humic ions, is not generally employed to provide the missing qualitative information primarily because the identification of metal complexes within the already complex mixtures of humic substances is non‐trivial and time‐consuming to the extent of eliminating any possibility for real‐time manipulation of chelated analytes. Here, it is demonstrated that with tailored selection of the metal ion, it is possible to visually identify large numbers of metal‐humic complexes (∼500 for Be 2+ , ∼1100 for Mn 2+ , and ∼1500 for Cr 3+ ) in real‐time as the spectra are being acquired. Metal ions are chosen so that they form primarily even‐ m/z complexes with humic ions. These even‐ m/z complexes stand out in the spectrum and can readily be characterized based on molecular formulae, which here revealed for example that Suwannee River fulvic acid (SRFA) complexes encompassed primarily highly oxygenated fulvic acids of relatively low double‐bond equivalence. Facile, real‐time identification of even‐ m/z metal‐humic complexes additionally allows for the specific selection of metal‐humic complexes for MS n analysis and in‐trap ion‐neutral reactions enabling investigation of metal‐humic complex structure. MS/MS data were collected to demonstrate the potential of the technique as well as highlight some of the remaining challenges. Copyright © 2009 John Wiley & Sons, Ltd.

This content is not available in your region!

Continue researching here.

Having issues? You can contact us here