Synergistic effect of MoS2 and diamond nanoparticles in electrochemical sensors: determination of the anticonvulsant drug valproic acid

Abstract

The authors describe an electrochemical sensor based on the use of diamond nanoparticles (DNPs) and molybdenum disulfide (MoS) platelets. The sensor was applied to the voltammetric determination of the anticonvulsant valproic acid which was previously derivatized with ferrocene. The MoS platelets were obtained by an exfoliation method, and the DNPs were directly dispersed in water and subsequently deposited on a glassy carbon electrode (GCE). The sensor response was optimized in terms of the solvent employed for dispersing the MoS nanomaterial and the method for modifying the GCE. Sensors consisting of a first layer of MoS dispersed in ethanol/water and a second layer of DNPs give better response. The single steps of sensor construction were characterized by atomic force microscopy and electrochemical impedance spectroscopy. The differential pulse voltammetric response of the GCE (measured at +0.18 V vs. Ag/AgCl) was compared to that of sensors incorporating only one of the nanomateriales (DNPs or MoS). The formation of a hybrid MoS-DNP structure clearly improves performance. The GCE containing both nanomaterials exhibits high sensitivity (740 µA ⋅ mM ⋅ cm), a 0.27 μM detection limit, and an 8% reproducibility (RSD). The sensor retained 99% of its initial response after 45 days of storage. Graphical abstract Electrochemical sensor by co-immobilization of MoS and diamond nanoparticles (DNP). The formation of a hybrid MoS-DNP structure enhances the performance of the sensor towards valproic acid derivatized with a ferrocene group, when compared with sensors incorporating only DNP or MoS.

Differential pulse voltammetric determination of the carcinogenic diamine 4,4′-oxydianiline by electrochemical preconcentration on a MoS2 based sensor

“…Most of the works related to the development of electrochemical sensors are based on the modification of a conventional electrode surface with hybrid structures of MoS 2 and other nanomaterial as metal nanoparticles [17][18][19][20], graphene [21][22][23], conductive polymers [24], or carbon nanotubes. [25,26] Our group has recently demonstrated the synergistic effect between MoS 2 nanosheets and diamond nanoparticles in the design of an electrochemical sensor for the determination of the anticonvulsant valproic acid [27]. Moreover, we have also obtained excellent results in the development of MoS 2 biosensors for lactate determination.…”

“…MoS 2 nanosheets are prepared by top-down solvent exfoliation following a procedure previously described [27,28]: 75 mg of MoS 2 are exfoliated in 10 mL EtOH/H 2 O (45%,v/v) by bath ultrasonication during 2 h. After 24 h at 4ºC, the suspension is centrifuged at 1500 rpm for 45 minutes. Finally, the supernatant is separated and stored at 4ºC.…”

Unveiling the Collaborative Effect at the Cucurbit[8]uril‐MoS2 Hybrid Interface for Electrochemical Melatonin Determination

“…The election of a TMD 2D platform is not arbitrary. First, it has shown excellent synergetic results towards determination of other analytes [10,11,26] and second, the chalcogenide termination induces a selectivity in the surface molecular adsorption. We have performed DFT geometrical relaxations and calculated the minimum energy for different geometries showing that the adsorption of a CB [8] on a TMD takes place with the plane defined by the oxygens perpendicular to the surface (both receptor portals are open), as indicated in Figure 3A.…”

Fluorescence enhancement of fungicide thiabendazole by van der Waals interaction with transition metal dichalcogenide nanosheets for highly specific sensors

“…The procedure followed for the synthesis of TMD suspensions was previously reported. 7 Briefly described: 75 mg of TMD (90 nm and 2 µm MoS 2 or 90 nm WS 2 ) were weighed in a glass vial and 10 mL of the dispersion solvent (NMP or EtOH/water, 45/55 v : v) were subsequently added. Once the vial was sealed, the mixture was subjected to batch ultrasonication for 2 h and the mixture was centrifuged at 1500 rpm for 45 minutes to remove aggregates.…”

“…[1][2][3][4] However, although there are some examples related to the use of TMDs for the development of chemical sensors, the benefits derived from their use are still not profusely explored. Recently, MoS 2 nanosheets have been proved to exhibit a synergistic effect when combined with other nanomaterials such as graphene, 5 gold nanoparticles 6 and diamond nanoparticles, 7 allowing the design of electrochemical sensors and biosensors with improved analytical properties. 8 Moreover, the interaction in solution of these nanomaterials with different compounds has been employed to develop new analytical methodologies, as this interaction leads to changes in light emission properties.…”