Influence of complexation phenomena with multivalent cations on the analysis of glyphosate and aminomethyl phosphonic acid in water

• Published in: Journal of Chromatography A Vol. 1175; no. 2; pp. 197 - 206
• Main Authors: Freuze, Ingrid, Jadas-Hecart, Alain, Royer, Alain, Communal, Pierre-Yves
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 21.12.2007; Elsevier
• Subjects: Adsorption; aminomethyl phosphonic acid; AMPA; Analysis methods; Analytical chemistry; Applied sciences; Calcium - chemistry; cations; Cations - chemistry; chemical reactions; Chemical Sciences; Chemistry; Chromatographic methods and physical methods associated with chromatography; Complexation; Computer Simulation; Copper - chemistry; Exact sciences and technology; Fluorenes - chemistry; FMOC derivatization; Glycine - analogs & derivatives; Glycine - analysis; Glyphosate; herbicide residues; high performance liquid chromatography; Iron - chemistry; Isoxazoles; metabolites; Metal interferences; multivalent cations complexation; Natural water pollution; Organophosphonates - analysis; Other chromatographic methods; Pollution; surface water; Tetrazoles; VMINTEQ modelling; water analysis; Water Pollutants, Chemical - analysis; water pollution; Water treatment and pollution; Zinc - chemistry; Complexation; VMINTEQ modelling; AMPA; Metal interferences; Glyphosate; FMOC derivatization; Chemical analysis; HPLC chromatography; Systemic; Derivatization; Modeling; Phosphorus Organic compounds; Iron II Ions; Fluorescence detector; Zinc II Ions; Pesticides; Interference; Stability constant; Organic phosphonate; Calcium Ions; Herbicide; Transition metal Ions; Medium effect; Fluorescent labelling; Aminoacid; Surface water; Water pollution; Copper II Ions; Organophosphonates; cations; Chemical; Adsorption; Calcium; Computer Simulation; Fluorenes; Iron; Copper; Glycine; Water Pollutants; Zinc
• ISSN: 0021-9673; 1873-3778
• DOI: 10.1016/j.chroma.2007.10.092

Experimental and theoretical influence of multivalent cations on the analysis of glyphosate and aminomethyl phosphonic acid (AMPA) was studied in pure water and in one surface water. The procedure chosen, based on derivatization with FMOC-Cl, HPLC separation, and fluorescence detection, appears highly affected at cations concentrations current in natural waters. A detailed speciation study performed with the VMINTEQ software strongly suggests that the complexes formed between analytes and cations do not dissociate during the reaction and do not react with the derivatization agent, so that only the free forms are derivatized. These results point out the necessity of a pre-treatment to prevent these interferences, even in low salinity waters. The different ways conceivable are discussed in terms of kinetic and thermodynamic considerations.