Electrochemistry of Gd2(MoO4)3-rGO nanocomposite for highly sensitive and selective detection of hazardous hydroquinone and chloramphenicol

Past and Present of Electrochemical Sensors and Methods for Amphenicol Antibiotic Analysis

“…Other electrochemical sensors developed for CAP analysis were obtained by drop casting [ 61 , 65 , 69 , 84 , 105 , 112 , 113 ] or drop coating methods. Thus, for example, in the first approach a thin film was formed by dropping an ethanolic graphene nanoflakes dispersion [ 50 ], a polydopamine functionalized vapor-grown carbon fiber composite slurry [ 94 ], DMF suspension of Co 3 O 4 @rGO [ 58 ] or of graphene/copper phtalocyanine [ 62 ], a solution containing gold nanoflowers, N-hydroxysuccinimide and graphene oxide [ 107 ], a dispersion in DMF of the nanocomposite carbon nanotubes/ethylene diamine/gold nanoparticles [ 118 ], Gd 2 (MoO 4 ) 3 @rG slurry in isopropyl alcohol and Milli-Q water [ 57 ], ZnWO 4 nanowires [ 90 ] or GO/PdNPs [ 66 ] ethanolic suspension, dispersion of Eu 2 O 3 NPs@rGO in water:ethanol [ 111 ] or of Fe/NC in deionized water:isopropyl alcohol:Nafion [ 88 ] on the electrode surface. This step was followed by drying in ambient conditions [ 50 , 57 , 65 , 66 , 88 , 94 , 105 , 107 , 111 , 113 ], at higher temperatures [ 59 , 61 , 84 , 112 ] or under vacuum [ 62 ].…”

“…With very few exceptions, the reduction signal C1 was exploited for CAP electrochemical quantification [ 80 ]. Investigation of the pH influence on this signal emphasized that the highest peak currents were usually obtained in PBS pH 7.00 [ 50 , 56 , 57 , 58 , 61 , 65 , 66 , 67 , 70 , 80 , 83 , 84 , 91 , 92 , 93 , 110 , 111 , 112 , 113 ] or 7.40 [ 55 , 62 , 74 , 105 , 107 ], but depending on the employed working electrode somewhat lower (BRB pH 5.00 at PGE [ 5 ]) or higher (pH 8.00 at Pt-Pd NCs/rGO/GCE [ 68 ]) values were established to be optimum. This observation was correlated with CAP pKa value (5.52) [ 48 , 92 ] and with the fact that CAP is easily hydrolyzed in both acidic and alkaline media [ 92 , 112 ].…”

“…Despite the fact that at most reported electrodes CAP electrochemistry followed the same pathway [ 50 , 58 , 60 , 61 , 62 , 65 , 66 , 67 , 74 , 83 , 84 , 89 , 93 , 94 , 97 , 110 , 111 , 113 , 115 ], the corresponding signals were shifted within some limits of about 0.200–0.300 V as can be observed from Figure 3 . On the other hand, the peak current variation with the scan rate emphasized that at some electrodes CAP reduction was diffusion controlled [ 5 , 50 , 57 , 60 , 61 , 62 , 74 , 84 , 89 , 90 , 91 , 110 , 111 , 112 , 113 ], whereas in other cases the electrode process was governed by the CAP adsorption on the sensor surface [ 55 , 65 , 66 , 67 , 72 , 83 , 87 , 94 , 97 , 105 , ...…”

“…The linear I p = f(v 1/2 ) (I p represents the peak current and v the scan rate) dependencies of the hydroquinone and CAP signals obtained simultaneously when they were in a mixture, emphasized diffusion-controlled processes of both compounds at Gd 2 (MoO 4 ) 3 @rG/GCE. However, the authors did not report the simultaneous quantitative analysis of the two substances [ 57 ].…”

Online Monitoring of Indole-3-acetic Acid in Living Plants Based on Nitrogen-Doped Carbon Nanotubes/Core–shell Au@Cu2O Nanoparticles/Carbon Fiber Electrochemical Microsensor

“…As a good candidate, electrochemical sensing technology has been developed to detect IAA due to the advantages of high sensitivity, low detection limit, and fast response. − In real sample applications presented in previous research, most IAA detection was performed by employing electrochemical sensors to detect IAA in the extracts of plant tissues in vitro. During the extraction process, however, IAA was easily decomposed by light irradiation, oxidation, or heating, resulting in partial loss .…”