Signal amplification by electro-oligomerisation for improved isoproturon detection

Abstract

A novel concept is introduced for signal amplification in electrochemical sensing: the electrooligomerisation stripping voltammetry, which has been applied here to the improved detection of the isoproturon herbicide in spring waters as a proof-of-principle. It involves a potentiostatic accumulation step onto a glassy carbon electrode (at +1.5 V vs Ag/AgCl reference electrode for 300 s) leading to the formation of an oligomeric film, which is then detected by cathodic stripping square wave voltammetry (SWV). The presence and composition of the film are confirmed by confocal Raman spectroscopy. Its characterisation by cyclic voltammetry demonstrates the reversible nature of the electrodeposited material, confirming its interest for sensitive detection by SWV. Adding a mesoporous silica membrane with vertically oriented nanochannels further enhances the sensitivity of the sensor, exhibiting a linear response in the 10-100 µM concentration range. This effect was even more interesting for real media analysis thanks to the permselective properties of such nanoporous coating in rejecting interferences and/or surface fouling agents. The method should be applicable to other analytes that are usually not detectable by conventional accumulation/stripping voltammetry.

Vertically Ordered Mesoporous Silica-Nanochannel Film-Equipped Three-Dimensional Macroporous Graphene as Sensitive Electrochemiluminescence Platform

“…On the other hand, APTES could be electrografted to carbon surface by forming C-N covalent bond through oxidizing its amine groups. At the same time, three silane groups of APTES are able to anchor VMSF ( Nasir et al, 2016 ; Nasir et al, 2018 ; Jiokeng et al, 2019 ; Nasir et al, 2019 ; Zhou et al, 2020b ; Nasir et al, 2020 ). Therefore, APTES can function as an effective molecular glue to improve the adhesion of VMSF to the surface of 3DG.…”

Composite Silica‐Based Films as Platforms for Electrochemical Sensors

“…[121,123-À 125,128,130,138,142,147,149,153,155,156] Many examples are given in Table 3 for the determination of various analytes, including drugs or pharmaceuticals, [128,130,138,146] neurotransmitters [121,164] or other biologically relevant molecules, [121,153,156,164] pesticides, [124,142,144,148,149,155] and hydroquinone derivatives. [123,125] In many cases, the analytical procedure clearly involves the accumulation of the analyte in the film prior to its electrochemical detection on the electrode substrate (i. e., by electrostatic binding of cations [121,128,130,142,146,148,149,153,164] or the formation of hydrogen bonds [123,125,153,155] or both, [156] or via electrooligomerization [144] ), but in some cases it is difficult to make a real distinction between a possible preconcentration in the film and a direct electrocatalytic detection on the nanocarbon surface, both being expected to enhance the voltammetric signals. Also, synergetic effects and electrocatalytic behaviour are sometimes claimed [124,142,149] but rarely demonstrated by both a signal enhancement and a noticeable decrease in the overpotentials.…”

“…Many examples are given in Table 3 for the determination of various analytes, including drugs or pharmaceuticals, [128,130,138,146] neurotransmitters [121,164] or other biologically relevant molecules, [121,153,156,164] pesticides, [124,142,144,148,149,155] and hydroquinone derivatives [123,125] . In many cases, the analytical procedure clearly involves the accumulation of the analyte in the film prior to its electrochemical detection on the electrode substrate ( i. e ., by electrostatic binding of cations [121,128,130,142,146,148,149,153,164] or the formation of hydrogen bonds [123,125,153,155] or both, [156] or via electro‐oligomerization [144] ), but in some cases it is difficult to make a real distinction between a possible preconcentration in the film and a direct electrocatalytic detection on the nanocarbon surface, both being expected to enhance the voltammetric signals. Also, synergetic effects and electrocatalytic behaviour are sometimes claimed [124,142,149] but rarely demonstrated by both a signal enhancement and a noticeable decrease in the overpotentials [121,146,155] .…”

Silica Nanochannel Array Film Supported by ß-Cyclodextrin-Functionalized Graphene Modified Gold Film Electrode for Sensitive and Direct Electroanalysis of Acetaminophen

“…The derivatization of nanochannels is mainly realized through the introduction of organic functional groups or nanomaterials. Generally, SNF containing organic reaction groups (e.g., -NH 2 or -SH) can be synthesized through co-polycondensation of silanes precursors containing functional groups ( Yan et al, 2016 ; Nasir et al, 2019 ; Nasir et al, 2020 ; Zhou et al, 2020 ). Subsequent reactions with -NH 2 or -SH, organic molecules (e.g., ferrocene, tetrazine, hydroquinone, etc.)…”