Analyzing several chelating agents and their effect on elemental composition of Lolium perenne and two growth media by capillary zone electrophoresis and inductively coupled plasma optical emission spectrometry

摘要

Capillary zone electrophoresis (CZE) along with ICP-OES was used for the determination of several chelating agents in clay and black soil, and in plants (Lolium perenne) grown in these matrices. Elemental levels in all the samples (Al, As, Ca, Cd, Cu, Fe, K, Mg, Mn, Pb, S and Zn) were investigated by inductively coupled plasma optical emission spectrometry (ICP-OES). Compared to previous methods, much shorter total analysis times were accomplished by the validation of an internal standard method for CZE analysis. The solubility of elements increased noticeably in the soils treated by the chelating agents before cultivation, and this phenomenon was strictly metal complex stability constant dependent. The most persistent chelating agents were triethylenetetraaminehexaacetic acid (TTHA) and 1,3-diaminopropanetetraacetic acid (PDTA). Both agents were bound to the growth medium and taken up by ryegrass, while only small proportions of them were degraded during cultivation. Diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA) and nitrilotriamineacetic acid (NTA), mainly bound to the clay matrix during the 19 days cultivation, but after 40 days cultivation in black soil they were degraded to smaller acids. The results clearly show uptake of chelating agents by plants and are a clear indication of the degradation of chelating agents. Keywords Chelating agent uptake by plants - Capillary zone electrophoresis - Emission spectrometry - Internal standard - Solubility of metals