An amperometric sensor based on Ni1-xAlx(OH)2NO3x×nH2O layered double hydroxide (LDH) has been developed for the electrochem. anal. in one step of two herbicides: glyphosate (N-(phosphonomethyl)glycine, Glyp) and glufosinate ((DL-homoalanine-4-yl)-methylphosphinic acid, Gluf). NiAl-LDH was prepd. by copptn. or by electrodeposition at the Pt electrode surface. Inorg. films were fully characterized by X-ray diffraction, Raman spectroscopy and SEM. Adsorption isotherms of Glyp onto this inorg. lamellar material have been established. Electrocatalytic oxidn. of Glyp and Gluf is possible at the Ni3+ centers of the structure. The electrochem. responses of the NiAl-LDH modified electrode were obtained by cyclic voltammetry and chronoamperometry at 0.49 V/SCE as a function of herbicide concn. in 0.1 M NaOH soln. The electrocatalytic response showed a linear dependence on the Glyp concn. ranging between 0.01 and 0.9 mM with a detection limit of 1 mM and sensitivity 287 mA/M cm2. The sensitivity found for Gluf was lower (178 mA/M cm2).
Glyphosate and glufosinate detection at electrogenerated NiAl-LDH thin films
SCAVETTA, ERIKA;BALLARIN, BARBARA;GUADAGNINI, LORELLA;TONELLI, DOMENICA
2009
Abstract
An amperometric sensor based on Ni1-xAlx(OH)2NO3x×nH2O layered double hydroxide (LDH) has been developed for the electrochem. anal. in one step of two herbicides: glyphosate (N-(phosphonomethyl)glycine, Glyp) and glufosinate ((DL-homoalanine-4-yl)-methylphosphinic acid, Gluf). NiAl-LDH was prepd. by copptn. or by electrodeposition at the Pt electrode surface. Inorg. films were fully characterized by X-ray diffraction, Raman spectroscopy and SEM. Adsorption isotherms of Glyp onto this inorg. lamellar material have been established. Electrocatalytic oxidn. of Glyp and Gluf is possible at the Ni3+ centers of the structure. The electrochem. responses of the NiAl-LDH modified electrode were obtained by cyclic voltammetry and chronoamperometry at 0.49 V/SCE as a function of herbicide concn. in 0.1 M NaOH soln. The electrocatalytic response showed a linear dependence on the Glyp concn. ranging between 0.01 and 0.9 mM with a detection limit of 1 mM and sensitivity 287 mA/M cm2. The sensitivity found for Gluf was lower (178 mA/M cm2).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
