MoS2 Quantum Dots-based Low-cost and Disposable Electrochemical Sensor for the Detection of Lead (II) Ions

Abstract

After the discovery of graphene, two-dimensional (2D) nanomaterials have received great attention due to their excellent physico-chemical properties. Application of 2D-nanomaterials as receptors of a sensor can achieve high sensitivity and specificity as every atom of the material directly interacts with the analyte. In the present work, MoS2 quantum dots (MSQD) for the ultrasensitive electrochemical detection of lead (Pb2+) ions. MSQDs were prepared by mechanical shear exfoliation method. Size of the QDs and inter planar distance of the crystalline QDs were studied using transmission electron microscope (TEM). The prepared quantum dots were drop casted on a shiny surface of well-polished pencil graphite electrode (PGE). In order to obtain the highest sensitivity for Pb2+-ion sensing, anodic stripping DPV (ASDPV) was employed and consequently, the effect of pH, deposition potential and time were optimized. The sensor shows a linear range from 5.66 × 10−9 M to 491.93 × 10−9 M with a calculated detection limit 1.96 × 10−9 M for the detection of Pb2+-ion. The sensor’s response for Pb2+-ion was unaffected in the presence of any other metal ions. A remarkable average recovery percentage around 99.50% from the Pb2+-ion spiked agriculture soil and ground water samples proves the practical applicability of the sensor.