A supramolecular hybrid sensor based on cucurbit[8]uril, 2D-molibdenum disulphide and diamond nanoparticles towards...

We develop an electrochemical sensor by using 2D-transition metal dichalcogenides (TMD), specifically MoS₂, and nanoparticles stabilized with cucurbit[8]uril (CB[8]) incorporated together with them. Two different nanoparticles are assayed: diamond nanoparticles (DNPs) and gold nanoparticles (AuNp). 0D materials, together with TMD, provide increased conductivity and active surface while the macrocycle CB[8] affords selectivity towards the guest methyl viologen (MV²⁺), also named paraquat. Glassy Carbon (GC) electrodes are modified by drop-casting of suspensions of MoS₂, followed by either a CB[8]-DNPs hybrid dispersion or a CB[8]-AuNp suspension. Atomic force microscopy is employed for the morphological characterization of the electrochemical sensor surface while cyclic voltammetry and electrochemical impedance spectroscopy techniques allow the electrochemical characterization of the sensor. The well-stablished signals of CB[8]-encapsulated MV²⁺ arise in voltammetric measurements when the macrocycle modifies the 0D-materials. Once the sensor construction and differential pulse voltammetry parameters have been optimized for quantification purposes, calibration procedures are performed with the platform GC/MoS₂/CB[8]-DNPs. This sensing platform shows linear relations between peak intensity and the MV²⁺ concentration in the linear concentration range of (0.73-8.0) · 10^-6 M with a limit of detection of 2.2 · 10^-7 M. Analyses of river water samples fortified with MV²⁺ at the μM level shows recoveries of 100% with RSD values of 6.4% (n = 3).