Cyclam‐Functionalized Silica‐Modified Electrodes for Selective Determination of Cu(II)

Abstract

Cyclam derivatives have been grafted via 1, 2 or 4 silylated arms to the surface of mesoporous silica and the resulting materials have been incorporated into carbon paste electrodes and applied to the preconcentration electroanalysis of Cu(II). Sensitive and selective detection of the target analyte was achieved owing to the attractive binding properties of this macrocyclic ligand towards Cu(II) species. Various parameters likely to affect the preconcentration and detection steps have been studied, including pH of the accumulation medium, composition of the detection solution, structure and composition of the adsorbent, accumulation time, or presence of potentially interfering species. In particular, the effect of the number of silylated groups linking the macrocycle to the silica network on the sensor performance was discussed. After optimization, Cu(II) can be determined in a linear concentration range extending from 2 nM to 100 mM. The method was validated by reliable Cu(II) determination in tap water.

Voltammetric Detection of Lead(II) Using Amide‐Cyclam‐ Functionalized Silica‐Modified Carbon Paste Electrodes

“…3 times for TETAM-mono and 2 times for TETAM-di). This effect, which is due to faster mass transport in mesostructured solids compared to the nonordered ones [66], is however not overwhelming if compared to what was observed for, e.g., Hg(II) detection at thiol-functionalized silica-based materials [23], but it is of the same order of magnitude even slightly better than that reported for the determination of Cu(II) using cyclam-functionalized silica-modified electrodes [53]. A possible explanation could be again a kinetic control of the formation of surface complexes in the confined environment (as discussed above), which would counterbalance the advantage of ordered mesoporous materials usually observed in terms of enhanced mass transport.…”

“…Accessible concentrations for Pb(II) were typically in the ppb to ppm range, with detection limits reaching 0.5 -1 ppb (2 -5 Â 10 À9 M) [46 -50, 52]. In a recent paper, we have introduced a novel family of silica-based electrode modifiers, namely the cyclam-grafted silica gels and mesoporous silicas, which were incorporated into CPEs and then applied to the selective voltammetric detection of Cu(II) owing to the great affinity of the cyclam ligand for this metal ion [53]. Actually, polyazamacrocycles of the cyclam family are known to form stable complexes with a large number of transition metals [54], the selectivity of which being tuneable by judicious functionalization of the ligand scaffold [55,56].…”

“…Solutions of metal ions used in the interference studies have been prepared from the following salts: Ni(NO 3 ) 2 Functionalized silica samples have been prepared from both a commercially available silica gel (chromatographic grade Kieselgel K60, Merck) and a well-ordered mesoporous silica powder (SBA-15 type). This latter was synthesized as previously described by our group [53,59]; the sample used in this work was characterized by a well-defined hexagonal mesostructure with mesochannels of 60 pore diameter, which is of the same order of magnitude as the average pore size of the nonordered K60 sample (70 ). 1 H and 13 C NMR spectra were recorded on a Bruker DRX-300 AVANCE Fourier transform spectrometer operating at 300 MHz at the Plateforme dAnalyse Chimique et de Synthè se Molé culaire de lUniversité de Bourgogne.…”

Carbon paste electrodes in the new millennium

“…Other examples are available for the detection of Cu(II) at CMCPEs with amine- [230], carnosine- [231], sulphonic acid- [232] or cyclam- [233] functionalized silicas, for the determination of Hg(II) with thiolfunctionalized materials [234] or for the accumulation and quantification of Pb(II) ions, in this case using a CPE modified with a heterogeneous material represented by self-assembled monolayers of acetamide-phosphonic acid on mesoporous silica [235].…”

Amino‐Containing Ultrafine Organosilica‐Nanoparticle‐Modified Au Electrode for the Determination of Cu(II) Ions

“…With the development of the chemically modified electrode, the electroanalysis application of organic/inorganic hybrids silica modified electrodes with functional group, such as aminoor thiol functional group, is now well-established in preconcentration analysis, electrocatalysis and biosensors [6][7][8][9][10], due to its large surface area and ordered porous structure. Organosilanes with functional groups are covalently linked on the surface either by post-synthetic grafting [11][12][13] or by co-condensation [14][15][16]. For post-synthetic grafting, a complicated chemical process was needed, and the amount and location of the incorporated functional group is difficult to control.…”