Electrochemical Detection of Analgesics in Biological Fluids

Accurate measurement of analgesic concentrations in biological fluids underpins effective pain management, therapeutic monitoring and toxicology. Traditional chromatographic techniques, while highly precise, often demand complex sample preparation, long analysis times and centralised laboratory facilities. Electrochemical detection has emerged as a compelling alternative, offering rapid response, minimal reagent consumption and potential for miniaturisation. By exploiting redox reactions at modified electrode surfaces, these sensors can quantify opioids and non-opioid analgesics—including tramadol and paracetamol—directly in matrices such as plasma, urine and saliva. Recent advances in nanomaterials, hybrid composites and green synthetic routes have enhanced electrocatalytic activity, selectivity and sensor stability, enabling sub-micromolar limits of detection within complex biological milieus. Ongoing efforts seek to integrate these platforms into point-of-care formats, paving the way for decentralised, real-time monitoring of analgesic dosing and clearance in clinical and forensic settings.

Research from Nature Portfolio

Recent studies have demonstrated the design of a carbon-paste electrode modified with copper oxide nanoparticles and multi-walled carbon nanotubes, synthesised via a green co-precipitation route. Characterisation by X-ray diffraction and electron microscopy confirmed a high-purity, low-agglomeration CuO phase intimately interfaced with nanotubes. Electrochemical analysis showed well-separated oxidation peaks for tramadol, with a linear detection range spanning 0.08 to 500 µM and a detection limit down to 0.025 µM. Density functional theory calculations supported the experimental finding of favourable charge transfer at the CuO–CNT interface. Validation in spiked biological samples achieved recoveries between 96 % and 104 %, illustrating the platform’s robustness for real-sample analysis.

Electrochemical Detection of Analgesics in Biological Fluids publication trend

The graph below shows the total number of articles in electrochemical detection of analgesics in biological fluids across all publications each year (not limited to Nature Index journals).

Technical terms

Electrochemical detection: Quantification of analytes through measurement of electrical currents or potentials generated by redox reactions at an electrode.

Differential pulse voltammetry: A sensitive voltammetric technique employing incremental potential pulses superimposed on a linear sweep to resolve closely spaced oxidation or reduction events.

Glassy carbon electrode: A chemically inert and electrically conductive carbon electrode material prized for its smooth surface and wide potential window.

Nanocomposite: A hybrid material in which nanoscale components (such as nanoparticles or nanotubes) are embedded within a matrix to enhance electrocatalytic performance.

Limit of detection: The lowest analyte concentration that produces a signal distinguishable from the background noise with defined confidence.

References

1. A UiO-66-NH2 MOF/PAMAM Dendrimer Nanocomposite for Electrochemical Detection of Tramadol in the Presence of Acetaminophen in Pharmaceutical Formulations. Biosensors (2023).
2. CuONPs/MWCNTs/carbon paste modified electrode for determination of tramadol: theoretical and experimental investigation. Scientific Reports (2023).
3. A Screen-Printed Electrode Modified With Graphene/Co3O4 Nanocomposite for Electrochemical Detection of Tramadol. Frontiers in Chemistry (2020).