Advances in Food Safety with a High-Sensitivity Mercury Detection Sensor

By Dr. Noopur JainReviewed by Susha Cheriyedath, M.Sc.Oct 30 2024

In a recent study in Proceedings, researchers revealed a breakthrough sensor technology that leverages square wave anodic stripping voltammetry (SWASV) to detect mercury in food samples

Background

Mercury contamination in aquatic ecosystems stems from both natural and human activities, leading to its bioaccumulation in various organisms. Mercury (Hg(II)), a highly toxic contaminant, accumulates in the human body via the food chain and can cause serious health problems, such as neurological damage and developmental issues in fetuses, even at low exposure levels.

Growing concerns about food safety have driven the development of advanced analytical techniques to detect hazardous substances in food. However, traditional methods for mercury detection are often complex and require costly equipment, limiting their suitability for routine food safety assessments.

This study addresses these limitations by developing a smart sensor that combines nanocomposite materials with portable electrochemical techniques. The sensor uses screen-printed graphite electrodes modified with poly(L-aspartic acid) and gold nanoparticles to enhance the electrochemical response, allowing for efficient mercury detection.

Research Overview

This research focused on fabricating nanocomposite screen-printed graphite electrodes (GSPEs) through a two-step modification process.

First, poly(L-aspartic acid) was electrodeposited onto the graphite electrodes using cyclic voltammetry (CV). This was followed by the deposition of gold nanoparticles (AuNPs) using chronoamperometry. The modified electrodes were then characterized with electrochemical techniques, including cyclic voltammetry and electrochemical impedance spectroscopy, to assess their efficacy in mercury detection.

The sensor’s analytical performance was evaluated via square wave anodic stripping voltammetry (SWASV), a method that enables sensitive detection of trace mercury levels. Key parameters, such as deposition time and potential, were optimized for peak analytical performance.

Calibration curves were generated in both beaker and drop configurations, demonstrating the sensor’s broad dynamic range for mercury detection. With a limit of detection at 0.25 μg/L, the sensor shows strong potential for analyzing low mercury concentrations in food samples.

Results and Discussion

The study demonstrated that the optimized AuNPs@p(L-Asp)/GSPEs sensor showed excellent electrochemical performance in mercury detection. Calibration curves indicated a dynamic range of 1–60 μg/L in drop configuration and 1–100 μg/L in beaker configuration, with detection limits of 0.25 μg/L and 0.28 μg/L, respectively. These results underscore the sensor’s sensitivity for trace-level mercury detection, a key factor for food safety applications.

The sensor was then tested on real food samples—specifically, cricket flour and seaweed—which were prepared through microwave mineralization, following standard mercury analysis protocols. Results from the smart sensor closely matched those obtained by a reference method, confirming the sensor's accuracy and reliability. The integration of the sensor with a portable potentiostat and smartphone-enabled on-site analysis, showcasing its practicality for food safety monitoring.

The study also highlighted the benefits of using nanocomposite materials in sensor development. The combination of poly(L-aspartic acid) and gold nanoparticles significantly enhanced the sensor’s electrochemical response, improving sensitivity and selectivity for mercury. Additionally, the use of screen-printed electrodes added to the sensor's cost-effectiveness and ease of use, supporting its potential for widespread application in routine food safety assessment.

Conclusion

This research is a key step in the right direction for food safety. Utilizing square wave anodic stripping voltammetry at nanocomposite screen-printed graphite electrodes, the sensor provides a simple, fast, and cost-effective solution for detecting trace mercury levels in food samples. Its high sensitivity, broad dynamic range, and portability also make it ideal for on-site food safety monitoring.

With mercury contamination posing an ongoing public health risk, these findings highlight the value of reliable analytical techniques to safeguard food products. Future research could focus on optimizing the sensor’s performance further and extending its application to a wider range of food matrices, ultimately supporting improved food safety and public health protection.

Journal Reference

Vitale I.A., Selvolini G., et al. (2024). Smart Sensor for Mercury Detection in Novel Food. Proceedings, 97, 232. DOI: 10.3390/proceedings2024097232, https://www.mdpi.com/2504-3900/97/1/232