Voltammetric study of pyridine-2-aldoxime methochloride at poly(p-toluene sulfonic acid) modified glassy carbon sensor and its analytical applications

Stripping voltammetric determination of pyridine-2-aldoxime methochloride at the iron(iii) doped zeolite modified glassy carbon electrode

“…It is clear from the plot that the slope À31.3 mV per unit pH increase corresponds to a two-electron, one-proton process. The result is consistent with the literature report 12 and the reaction of PAM-2 at the modified electrode is likely to be: 29…”

“…The sensitivity of the modified electrode was 0.36 mA mM À1 and the detection limit was found to be 1.61 Â 10 À7 M based on the signal-to-noise ratio of 3, which is comparable to that obtained with the carbon nanotube modified GCE (3.0 Â 10 À7 M) 13 and larger than at the result at the poly(p-toluene sulfonic acid) (p-TSA) modified GCE (3.0 Â 10 À8 M). 12 The relative standard deviation (RSD) for five successive determinations of 25 mM PAM-2 at the modified electrode was 1.49%, which indicates a very good repeatability. The reproducibility of three Fe 3+ Y modified GCEs for the responses of 25 mM PAM-2 was evaluated and the RSD obtained was 4.63%.…”

“…Only a few voltammetric methods based on the poly(p-toluene sulfonic acid) modified glassy carbon electrode (GCE) 12 and multiwalled carbon nanotube modified platinum electrode 13 have recently been reported for the determination of PAM-2. Although these modified electrodes showed a good linear range, important analytical parameters such as stability and sensitivity of the methods were not reported.…”

Innovative approach for the electrochemical detection of non-electroactive organophosphorus pesticides using oxime as electroactive probe

“…An irreversible oxidation peak was observed at the GCE/PAM (curve b) and GCE/GQDs/PAM (curve d). The oxidation peak corresponded to the electrochemical oxidation of the aldoxime group of PAM to carbonyl group via a two-electron-transfer mechanism, which has been detailed discussed by previous literatures [15,16]. Compared with bare GCE, the oxidation potential of PAM at GCE/GQDs/PAM negatively shifted from +0.76 V to +0.71 V, and the oxidation current enhanced significantly.…”

“…By means of the favorable film-forming ability of chitosan, GQDs were uniformly immobilized on GCE. The net charges of carboxyl group on GQDs appear to be negative while the nitrogen atom on the pyridine ring of PAM appears to be positive [15,16], thus plenty of PAM molecules can be adsorbed on GQDs film due to electrostatic attraction. In addition, the p-p stacking interaction between GQDs and pyridine rings will increase the adsorption capacity and stability of immobilized PAM.…”