Electrochemical biomimetic sensor based on oxime group-functionalized gold nanoparticles and nitrogen-doped graphene composites for highly selective and sensitive dimethoate determination

2‐(Hydroxyimino)aldehydes: Photo‐ and Physicochemical Properties of a Versatile Functional Group for Monomer Design

“…A more detailed investigation of the chemical processes causing this lack of reversibility is in progress. Anyway, the results indicate that 2‐(hydroxyimino)aldehyde anions, with the exception of compound 11 − having a bulky substituent ( E p =0.38 V), are oxidized at higher potentials than simple aldoximes (CH 3 CH=NOH, E p =0.137 V/NHE; ( E )‐PhCH=NOH, E p =0.328 V/NHE) and ketoximes ((CH 3 ) 2 C=NOH, E p =0.181 V/NHE; Ph 2 C=NOH, E p =0.225 V/NHE) . Indeed, the oxidation potentials of the HIA anions are more similar to those of α‐ketoximes (CH 3 COCH=NO − , E p =0.558 V/NHE; PhCOCH=NO − , E p =0.540 V/NHE) bearing a carbonyl group conjugated to the >C=NO − moiety.…”

“…This property, which has attracted considerable attention towards oximes in the detoxification of organophosphorus compounds, levels off as the acidity of the parent oxime decreases . The capacity of oximes and their anions to form metal coordination complexes can be used in multiple‐analyte and/or electrochemical systems for the detection of metal ions or other organic species . The redox properties and acidity of oximes are important properties for assessing their potential for these applications.…”

“…The potentials were first swept to 2V/NHE. [40,41] Indeed, the oxidation potentials of the HIA anionsa re more similar to those of a-ketoximes (CH 3 COCH=NO À , E p = 0.558 V/NHE;P hCOCH=NO À , E p = 0.540 V/ NHE) [45] bearing ac arbonyl group conjugated to the > C=NO À moiety. After deprotonation with af our-fold excess of Me 4 NOH, all the 2-(hydroxyimino)aldehydea nions show two irreversible oxidation peaks (Table 4, Figure 6, and the Supporting Information), the first in the range of 0.38-0.64 V/NHE, the second at E > 1.1 V/NHE.…”

“…[11] Thecapacity of oximes andt heir anions to form metal coordinationc omplexesc an be used in multiple-analyte and/or electrochemical systemsf or the detection of metal ions or other organic species. [41] The redox properties and acidity of oximes are important properties for assessing their potential for these applications. In the case of HIAs, the presence of the electron-withdrawing CHO substituent on the C(=NOH) group is expected to enhance their acidity and affect the oxidation potential of their anionsw ith respectt ot he corresponding unsubstituted oxime/oximate pairs.…”

Heteroatom-Doped Graphene-Based Electrochemical Sensors for Toxic Chemicals

“…The ERNGO/GCE exhibited wide linearity of 5.0~850 μg/L with a detection limit of 1.0 μg/L (S/N= 3) under optimized conditions [81]. A layer by layer assembled of hexachlorobenzene (HCB) sensor has been demonstrated using the nitrogen-doped graphene(NG) and chitosan modified GCE [82][83]. The study pointed out that, the graphene structure makes very good adsorption affinity towards HCB and enhances the sensor activity.…”