Abstract
In this study, reduced graphene oxide (rGO) was electrochemically deposited on the surface of screen-printed carbon electrodes (SPCE) to prepare a disposable sensor for fast detection of Pb2+ in foods. The SEM images showed that the rGO was homogeneously deposited onto the electrode surface with a wrinkled nanostructure, which provided 2D bridges for electron transport and a larger active area for Pb2+ adsorption. Results showed that rGO modification enhanced the activity of the electrode surface, and significantly improved the electrochemical properties of SPCE. The rGO modified SPCE (rGO-SPCE) was applied to detect Pb2+ in standard aqueous solution, showing a sharp stripping peak and a relatively constant peak potential in square wave anodic stripping voltammetry (SWASV). The linear range for Pb2+ detection was 5∼200 ppb (R2 = 0.9923) with a low detection limit of 1 ppb (S/N = 3). The interference of Cd2+ and Cu2+ at low concentrations was effectively avoided. Finally, the rGO-SPCE was used for determination of lead in real tap water, juice, preserved eggs and tea samples. Compared with results from graphite furnace atomic absorption spectroscopy (GFAAS), the results based on rGO-SPCE were both accurate and reliable, suggesting that the disposable sensor has great potential in application for fast, sensitive and low-cost detection of Pb2+ in foods.
Highlights
Heavy metal contamination in food sources has become a very serious problem, especially in the developing countries
80 μL of the mixture was dropped onto the reduced graphene oxide (rGO)-screen-printed carbon electrode (SPCE)
The heavy metal detection was performed by square wave anodic stripping voltammetry (SWASV) with optimized parameters
Summary
Heavy metal contamination in food sources has become a very serious problem, especially in the developing countries. The most terrible consequence is that heavy metals cannot be eliminated from foodstuffs by soaking, washing, cooking or other methods. World Health Organization (WHO), levels of lead, cadmium, chromium, and other heavy metals must definitely be controlled in food sources in order to assure the public safety [1]. Protection Agency (EPA) has determined that lead is a probable human carcinogen, which can damage every organ and system in human body. Exposure to lead (Pb) at high levels can severely damage the brain and kidneys, and even cause death to human beings. High levels of exposure to lead may cause miscarriages [2], so it is critical to control and determine the heavy metal concentrations in food
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