Advances in mass spectrometry for iron speciation in plants

Abstract

Iron is an important nutrient essential for plants and critical for human health. The state-of-the art of methods for iron speciation in cereal grains and plant fluids is critically reviewed. Particular attention is given to the latest developments in the coupling of HPLC with the parallel ICP MS and electrospray ionization (ESI) MS/MS detection, usually QTOF MS or Q-Orbitrap MS, for the identification and quantification of iron species. The coupled techniques allow the direct microanalysis of plant intracellular fluids (xylem and phloem) and complement X-ray absorption spectroscopy (XANES and EXAFS). The increasing resolution and sensitivity of electrospray mass spectrometers and emergence of software allowing extraction of iron specific data from large chromatographic data sets are responsible for the growing role of electrospray MS/MS in speciation studies. The use of stable isotopes for the probing of the reactivity and stability of endogenous metal complexes and quantitative analysis are rising in importance.

Nontarget Approach to Identify Complexing Agents in Atmospheric Aerosol and Rainwater Samples

“…The respective iron complex consists of two completely deprotonated oxalic acid molecules which embrace the iron­(III)-cation ([2­(M – 2H) + Fe] − ). Such types of complexes were already reported in previous publications on iron complexes studied with LC/MS systems. , However, for succinic acid, a different complex type was found to be dominant. The m / z signal at 277.8610 (B) is caused by a complex of one single deprotonated succinic acid molecule ([M – H] − ) and FeCl 3 ([M – H + FeCl 3 ] − ).…”

“…Such types of complexes were already reported in previous publications on iron complexes studied with LC/MS systems. 14,26 However, for succinic acid, a different complex type was found to be dominant Previous studies described that the occurrence of additives such as FeCl 3 influences the complex speciation and signal responses. 27,28 Hence, Table S4 therefore gives an overview of all detected iron complexes and their relative intensities for the investigated carboxylic acids.…”

Molecular investigation of the multi-phase photochemistry of Fe(iii)–citrate in aqueous solution

“…Fe-citrate, Fe-malate, and Fe-siderophores). [80][81][82][83][84][85] A multistep gradient elution was performed at a ow rate of 0.2 mL min À1 using a binary mobile phase-buffer system: (A) LC/ MS-grade water (Optima™, Sigma Aldrich Inc.) with 10 mM ammonium acetate buffer (v/v) and (B) LC/MS-grade methanol (Optima™, Sigma Aldrich Inc.) with 10 mM ammonium acetate buffer (Sigma Aldrich Inc.). The buffer pH for all LC experiments was held within 5.2-6.8 to preserve the metal-ligand equilibria.…”

A Fast and Efficient Procedure of Iron Species Determination Based on HPLC with a Short Column and Detection in High Resolution ICP OES

“…Due to this, food fortification approaches exist that allow for the supplementation of iron, especially in developing countries with high iron deficiency among the population. The aim of such a program is to obtain modified crops that can efficiently accumulate this element from the soil [5], and due to the different uptake mechanisms, i.e., in the form of Fe(II) or Fe(III) complexes [6], knowledge about iron speciation in soils is required.…”