Graphene nanoplatelet/graphitized nanodiamond-based nanocomposite for mediator-free electrochemical sensing of urea. (15th January 2020)

• Record Type: Journal Article
• Authors: Kumar, Vanish; Kaur, Inderpreet; Arora, Saloni; Mehla, Ravi; Vellingiri, Kowsalya; Kim, Ki-Hyun
• Is Part Of: Food chemistry. Volume 303(2020)
• Publication Date: 2020-01-15
• Subjects: Graphene nanoplatelets -- Graphitized nanodiamonds -- Urea -- Sensing -- Screen-printed electrode; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2019.125375
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Urea, which is synthesized during the metabolism of N -containing compounds in mammals. Increasing urea levels in milk samples are suspected to reflect pathological problems. We developed direct and mediator-free urea sensors based on screen-printed electrodes (SPEs). To this end, graphene nanoplatelets/graphitized nanodiamonds (GNPlts/GNDs) was synthesized. The developed platform was a highly reliable and sensitive tool for the detection of urea. Abstract: Urea is well-known to offer tremendous scope for sensing/diagnosing such as adulteration in dairy products or diseases in human body. This study was organized to describe and validate a new mediator-free, unsophisticated, and direct current voltage (IV)-based sensor for facile detection of urea using nanocomposites made of urease-immobilized graphene nanoplatelets and graphitized nanodiamonds. This nanocomposite displayed sensitive and direct signal in the form of current at 0 V without the need of any complex chemical reaction. This platform was highly sensitive (limit of detection of 5 μg/mL) far superior to the comparable systems introduced recently. The incorporation of graphitized nanodiamonds within the graphene nanoplatelets layers helped improve the sensitivity by a factor of three (up to 806.3 µA (mg mL −1 ) −1 cm −2 ) with 20 s response time. As such, the use of this nanocomposite was helpful in improving sensing performances with enhanced enzyme loading capacity.