Determination of synthetic ferric chelates used as fertilizers by liquid chromatography-electrospray/mass spectrometry in agricultural matrices

Abstract

A high-performance liquid chromatography-electrospray ionization/mass spectrometry (time of flight) method has been developed for the simultaneous determination of synthetic . The average intraday repeatability values were ϳ0.5 and 5% for retention time and peak area, respectively, whereas the interday repeatability values were ϳ0.7 and 8% for retention time and peak area, respectively. The method was validated using four different agricultural matrices, including nutrient solution, irrigation water, soil solution, and plant xylem exudates, spiked with Fe(III)-chelate standards and their stable isotope-labeled corresponding chelates. Analyte recoveries found were in the ranges 92-101% (nutrient solution), 89 -102% (irrigation water), 82-100% (soil solution), and 70 -111% (plant xylem exudates). Recoveries depended on the analyte, with Fe(III)-EDTA and Fe(III)-DTPA showing the lowest recoveries (average values of 87 and 88%, respectively, for all agricultural matrices used), whereas for other analytes recoveries were between 91 and 101%. The method was also used to determine the real concentrations of Fe(III)-chelates in commercial fertilizers. Furthermore, the method is also capable of resolving two more synthetic Fe(III)-chelates, Fe(III)-EDDHSA and Fe(III)-ED-DCHA, whose exact quantification is not currently possible because of lack of commercial standards. (J Am Soc Mass Spectrom 2007, 18, 37-47)

CE of phytosiderophores and related metal species in plants

“…7, with increasing ACN content of the buffer solution, the CE separation of the two isomers of Fe(III)-EDDHA is getting better. At 60% ACN, there is already a base-line separation, and at 80% ACN, the separation is even better -and at least comparable to the published separations by HPLC [32,34], but faster. This demonstrates the suitability of this modified capillary for separation of isomers of metal species at neutral pH.…”

“…Hence, without the presence of a chiral column or modifier, two forms of Fe(III)-EDDHA should be separable. This separation was demonstrated already in HPLC [32,34], using different modes of separation. In Fig.…”

“…Only one peak for Fe(III)-EDDHA species was detected, while in HPLC two diastereomers of that chelate can be separated [32][33][34]. As will be shown in the next section, the two diastereomers can be separated also by CE, but other parameters are needed.…”

Surfactant and Nutrient Uptake in Citrus

“…Application of electrospray-ionisation time-of-fl ight mass spectrometry (ESI-TOF MS) has enabled accurate functional end-group identi fi cation and quanti fi cation of ionisable compounds by using exact mass/charge ( m / z ) ratio determinations of surfactant and Fe-containing mixtures (Alvarez-Fernández et al 2007 ) .…”

EDTA Shuttle Effect vs. Lignosulfonate Direct Effect Providing Zn to Navy Bean Plants (Phaseolus vulgaris L ‘Negro Polo’) in a Calcareous Soil

“…European regulation allows its application in fertirrigation, by foliar spray and recently, direct application to soil. Several authors tested the efficiency of ZnLS complexes in hydroponic culture conditions, in soil conditions or by foliar applications (Álvarez et al, 1996; Moraghan, 1996; Gangloff et al, 2002; Álvarez-Fernández et al, 2007; Gonzalez et al, 2008; Martín-Ortiz et al, 2009; Benedicto et al, 2011). …”