Strategy of In Situ Electrochemical Regulation for Highly Enhanced Nonenzymatic Sensing of Carbaryl

Abstract

Specific and sensitive sensing of most pesticide residues relies on enzymes such as acetylcholinesterase and advanced materials, which need to be loaded on the surface of working electrodes, leading to instability, uneven surface, tedious process, and high cost. Meanwhile, employing certain potential or current in electrolyte solution could also modify the surface in situ and overcome these drawbacks. However, this method is only regarded as electrochemical activation widely applied in the pretreatment of electrodes. In this paper, by means of regulating the electrochemical technique and its parameters, we prepared a proper sensing interface and derivatized the carbaryl (a carbamate pesticide) hydrolyzed form (1-naphthol) to enhance sensing by 100 times within several minutes. After regulation I by chronopotentiometry with 0.2 mA for 20 s or chronoamperometry with 2 V for 10 s, abundant oxygen-containing groups form and the ordered carbon structure is destroyed. Sweeping from −0.5 to 0.9 V through cyclic voltammetry for only one segment, following regulation II, the composition of oxygen-containing groups changes and the disordered structure is alleviated. Finally, on the constructed sensing interface, test by regulation III through differential pulse voltammetry from 0.8 to −0.4 V, resulting in derivatization of 1-naphthol during 0.8–0 V, followed by electroreduction of the derivative at around −0.17 V. Compared with the electro-oxidation peak at 0.5 V in previous reports, it is essential to improve specificity, even toward several other carbamate pesticides with similar structures. Hence, the in situ electrochemical regulation strategy has demonstrated great potential for effective sensing of electroactive molecules.

Co-Reactive Ligand In Situ Engineered Gold Nanoclusters with Ultra-Bright Near-Infrared Electrochemiluminescence for Ultrasensitive and Label-Free Detection of Carboxylesterase Activity

“…Therefore, 1-NA reduced the generation for DEAET–Au NCs intermediates by hole-capture competition, leading to the significantly quenching of ECL intensity of DEAET–Au NCs. Additionally, the consumption of DEAET–Au NCs excited states with 1,4-naphthoquinone (1,4-NQ) for the electro-oxidation product of 1-N was investigated . As shown in Figure E, the typical reducing agent NaBH 4 quenched the ECL intensity of DEAET–Au NCs due to its strong reducibility, consuming the electro-injected holes on the GCE surface (curve a, b).…”

“…Additionally, the consumption of DEAET−Au NCs excited states with 1,4-naphthoquinone (1,4-NQ) for the electrooxidation product of 1-N was investigated. 38 As shown in Figure 4E, the typical reducing agent NaBH 4 quenched the ECL intensity of DEAET−Au NCs due to its strong reducibility, consuming the electro-injected holes on the GCE surface (curve a, b). Nevertheless, in the presence of CE and 1-NA, the ECL signal of DEAET−Au NCs containing NaBH 4 was higher than that of DEAET−Au NCs without NaBH 4 (curve c, d), which was because NaBH 4 reduced 1,4-NQ in advance to avoid the occurrence of the reaction between 1,4-NQ and DEAET−Au NCs excited states.…”

Subtle adjustment of the cyclic potential on electro-activated glassy carbon electrodes for sensitive sensing of methyl parathion

“…The effect of cyclic potential applied to the electrode during electrochemical activation is mainly dependent on two key factors: sweep segments and potential range. 15,17 In general, a "sweep segment" means a one-way cycle between high potential and low potential while the two segments are one circle. To explore whether changing these two parameters can further improve the signal response of MP on e-GCEs, we recorded the peak current of MP on e-GCEs under different sweep segments and potential ranges.…”

“…[7][8][9] However, more and more research found that the effect of electro-activation during the whole process of preparation and testing has been underestimated or even ignored. [10][11][12][13][14] Recently, electro-activated GCEs (e-GCEs), typically prepared by high-potential potentiostatic polarization or potential cycling over a wide potential range, have emerged and been applied for detecting various electro-active analytes like imidacloprid, 11,15 hydroquinone, 6 catechol, 16 carbaryl, 17 uric acid, 18 paracetamol, 19 tert-butylhydroquinone, 20 and so on. Compared with the much more widely adopted modication with biochemical elements, the advantages of e-GCEs include high stability, facile fabrication, low cost, environmental protection, and user-friendliness.…”

“…To avoid endless trials and explore the performance limitation, how and why these factors affect the analysis performance is essential to make clear, especially the vital factors such as potential, because different potentials bring about different changes on the surface of the e-GCE, resulting in different responses to the analyte. 17,21 At present, the potential is always provided by cyclic potential 5,22 and constant potential (known as anodizing and cathodizing), 19,23,24 and another changeable potential (constant current) 25 sometimes. At the same time, the parameters of the potential are focused on several certain values with little theoretical basis.…”