Eco-Friendly Method Detects Illicit Drugs in Just Five Minutes

A research team from the University of Córdoba has developed an innovative and eco-friendly method for detecting trace amounts of illicit drugs on surfaces. This new technique can determine the exact quantity of drugs in just five minutes, utilizing common household items such as cotton fabric swabs for sampling.

The research group, known as FQM-215—Affordable and Sustainable Sample Preparation, has created a process that is both faster and more environmentally sustainable than traditional methods. According to Carlos Calero Cańuelo, a key member of the research team alongside Rafael Lucena and Soledad Cárdenas, the method consists of two main stages: sampling and analysis.

Innovative Sampling and Analysis Techniques

In the initial sampling stage, the team has significantly reduced the use of toxic chemicals, minimizing the test’s environmental impact. A simple cotton fabric swab, which is highly absorbent due to its cellulose composition, is moistened with a few drops of methanol. This combination effectively captures drug residues from various surfaces.

Once the cotton swab has absorbed the substances, the analysis begins. The method employs thermal desorption, a process that involves the evaporation of the target compounds, combined with mass spectrometry. This analytical technique is crucial for identifying molecules in a sample and determining the type and quantity of the drugs present.

After sampling, the swab is heated in a specialized interface, causing the target compounds to evaporate. These compounds then enter a second phase where they are ionized using plasma, giving them a positive charge. This process allows the mass spectrometer, which uses electromagnetic fields, to accurately detect and measure the drugs. As Calero Cańuelo explains, “The use of mass spectrometry allows us to achieve very high levels of sensitivity and selectivity.”

High Precision for Forensic Applications

The precision of this method is remarkable; it can detect drug residues as small as 4 nanograms on a 100-square-centimeter surface, highlighting its effectiveness even for traces that are invisible to the naked eye. Published in the journal Analytica Chimica Acta, this technique has been validated across various drugs, including cocaine, methadone, and codeine, and has been tested on different surfaces as well as cotton swabs of various colors.

The combination of speed, accuracy, and simplicity makes this method particularly well-suited for applications in forensic science, drug control, criminal investigations, and laboratory settings. The implications of this research extend beyond academic interest, potentially contributing to enhanced drug detection capabilities in various sectors.

For further information, refer to the study by Carlos Calero-Cañuelo et al, titled “Quantitative determination of drug residues in surfaces, analyzing cotton-swabs by on/off thermal desorption-plasma based ionization-mass spectrometry,” published in Analytica Chimica Acta on November 26, 2025. The DOI for the study is 10.1016/j.aca.2025.344630.