Improving Tannic Acid Detection in Food and the Environment

Recently, a team of researchers from Gannan Medical University explored how to improve tannic acid contamination in food and environmental analysis. This study, which was published in the journal Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, presents a new dual-mode sensing system that can improve detection of tannic acid (1). This system, powered by sulfur quantum dots (SQDs) and manganese dioxide (MnO₂) nanocomposites, showcases the latest advancement in portable spectroscopic instrumentation (1).

What is tannic acid?

Tannic acid is a polyphenol that is used as a flavoring agent in food and beverages (2). Tannic acid also has applications in medicine and manufacturing, where it is used to treat conditions such as rashes and cold sores, as well as in ointments (2). Because of the numerous application areas tannic acid is used in, it is becoming increasingly found in food and in the environment. This is concerning because excessive tannic acid could result in harm to human health and the environment.

The newly developed SQDs/MnO₂ nanocomposite acts as a high-activity nanozyme designed to rapidly detect tannic acid concentrations. The results in the study showed that the composite material shows a notably low Michaelis–Menten constant (0.117 mM) toward 3,3′,5,5′-tetramethylbenzidine (TMB), reflecting strong catalytic affinity and reaction efficiency (1). The nanozyme catalyzes the production of hydroxyl radicals (•OH) from oxygen, which in turn oxidize TMB and produce a distinct blue color (1). When TA is present, however, it scavenges the generated radicals, preventing the blue coloration and providing a measurable signal for detection (1).

What is the importance of this sensor?

This sensor’s mechanism supports a dual-mode platform, which makes the device more user friendly and practical for real-world applications. The sensor, because of these modifications, can do traditional colorimetric measurement as well as smartphone-based digital analysis (1). This development is important because it shows that this sensor can help contribute toward eliminating our dependence on expensive spectroscopic instruments that are primarily used in tannic acid detection.

The success of the platform is rooted in the synthesis strategy. The team first prepared water-soluble and stable SQDs using a simple one-pot solvothermal method, followed by hydrothermal synthesis to create three-dimensional flower-like SQDs/MnO₂ nanostructures (1). This architecture enhances surface area and electron transfer efficiency, ensuring strong nanozyme performance for tannic acid monitoring (1).

To validate real-world usability, the researchers applied their sensing system to a range of complex matrices, including red wine, white wine, lake water, and soil. In each case, accurate quantitative detection of tannic acid was achieved, demonstrating robustness across differing sample compositions (1).

What are the key takeaways from this study?

With food safety and environmental integrity under increasing scrutiny, new tools are needed to detect harmful components, such as tannic acid, in the environment and in our food. This new study reveals that portable instrumentation, such as this sensor, is making strides in this space.

“We developed a novel colorimetric and smartphone sensing platform for the accurate and sensitive detection of TA in food and environmental samples,” the authors wrote in their study (1). “This strategy eliminates the need for expensive instrumentation and offers a straightforward method for quantitative TA detection.”

Other related articles: How Portable Raman Spectroscopy Systems Can Lead to Affordable Kidney Disease Diagnostics

Using Spectroscopic Sensors in Creating a New Beverage Recognition System that Improves on Smartphone Apps

References

1. Huang, Y.; Liu, Y.; Liao, N.; et al. Boosting Manganese Dioxide Nanozyme Activity with Sulfur Quantum Dots for Colorimetric and Smartphone-based Detection of Tannic Acid. Spectrochimica Acta Part A: Mol. Biomol. Spectrosc. 2025, 348 Part 2, 127095. DOI: 10.1016/j.saa.2025.127095
2. WebMD, Tannic Acid - Uses, Side Effects, and More. WebMD. Available at: https://www.webmd.com/vitamins/ai/ingredientmono-217/tannic-acid (accessed 2025-11-18).