Chemosensors detect food contaminants

Quality assurance in the food industry requires reliable, rapid, and cost-effective methods for the early detection of chemical contaminants – such as pesticides, drugs, or drug residues – in raw materials like milk, wheat, or honey. Today’s supply chains are complex, and contamination can cause significant economic damage if contaminated raw materials are not identified until it is too late.

State of the art

The standard in analytical testing relies primarily on chromatographic methods. These methods are time-consuming and cost-intensive, as they require specialized laboratory equipment and trained personnel, and they demand extensive sample preparation. While they provide detailed substance identification, they are not suitable for rapid decision-making along the production chain or for mobile testing scenarios. Existing rapid tests often rely on biological detection systems such as antibodies that are immobilized on electrode surfaces. The high cost and complexity prevent mass-market applications.

Technology

Researchers at the Institute of Nanotechnology (INT) at KIT have developed a simple, robust, and low-cost rapid electrochemical testing method. It is based on chemosensors consisting of a barrel-shaped macrocycle molecule. This molecule has a cavity to which an indicator is stably bound, producing only a weak electrochemical signal. If an analyte – such as a pesticide – is present in the sample, it binds more strongly to the macrocycle than the indicator. The analyte displaces the indicator from the cavity and takes its place. The released indicator is easily oxidized, generating a strong current signal. The sensor thus reliably indicates the presence of contamination even at low concentrations, without needing to specifically identify the pollutants.

Advantages

This electrochemical analysis is highly sensitive and is performed directly in the sample within a few seconds with minimal preparation. Samples may need to be liquefied or filtered. The measurement system requires only a standard miniature electrode. No specialized personnel are required. Furthermore, it is suitable for point-of-care applications, such as the rapid on-site testing of liquids.

Options for companies

KIT is looking for partners in the food industry, quality control, and diagnostics to produce market-ready test kits, develop compact measuring devices, or integrate them into existing quality assurance processes.