Researchers at the University of Córdoba have developed a fast, precise, and environmentally sustainable method for detecting trace residues of illicit drugs on surfaces. Described in Analytica Chimica Acta, the technique uses common cotton fabric, minimal solvent, and advanced analytical instrumentation to identify and quantify drugs in less than five minutes.
Developed by the FQM-215 research group, the method integrates two stages: sampling and analysis. In the first step, a moistened cotton fabric swab is used to collect drug residues from a surface. The choice of cotton – a cellulose-based, absorbent material – is both environmentally friendly and highly effective at capturing trace compounds. The swab is lightly wetted with methanol, minimizing solvent use and reducing waste.
The second stage involves introducing the swab into a thermal desorption interface. Heating the swab releases the captured analytes, which are then ionized using a low-temperature plasma source. The ions are detected and measured using a mass spectrometer, allowing researchers to determine both the identity and quantity of the drugs present.
This combination of techniques enables detection limits as low as 4 nanograms over a 100 cm² surface area – well below levels visible to the naked eye. “The use of mass spectrometry allows us to achieve very high levels of sensitivity and selectivity,” said Carlos Calero Cañuelo in the University’s press release.
The method has been validated across a range of substances, including cocaine, codeine, and methadone, and performs reliably on different surfaces and cotton swab colors. Its efficiency and minimal environmental footprint make it particularly well-suited for forensic investigations, drug enforcement, and clinical monitoring applications.
With its combination of simplicity, speed, and accuracy, the method holds strong promise for applications in forensic science, law enforcement, and clinical toxicology. Its low reagent use and compatibility with reusable materials also align well with green analytical chemistry principles – potentially enabling broader adoption of sustainable practices in routine drug monitoring.
Simplicity for Sustainable Sample Preparation
Soledad Cárdenas, co-author of the study, discussed with us earlier this year how small shifts in sample preparation can drive greater sustainability in analytical labs. “Simple sample preparation necessitates daily work with an open mind and creativity with the elements we commonly have to hand. But the rewards – contributing to the sustainability and affordability of the amazing activities we perform as analytical chemists – are certainly worth it.”
Read the full article here.
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