Surface-Enhanced Raman Spectroscopy Applications in Forensic Analysis

Surface-enhanced Raman spectroscopy (SERS) has emerged as a powerful analytical technique in forensic science by combining molecular fingerprinting with ultrasensitive detection of trace evidence. The method exploits plasmonic substrates—typically noble metal nanoparticles or nanostructured films—to amplify inherently weak Raman scattering signals by several orders of magnitude. As a result, SERS can identify minute quantities of illicit drugs, explosive residues, dyes, inks and biological fluids without extensive sample preparation. Its compatibility with portable and handheld instruments, including smartphone-based detectors, enables on-scene screening by law enforcement and customs agents. Advances in substrate design, chemometric data processing and integration with complementary imaging modalities have extended multiplexed quantification to complex matrices such as saliva, urine and wastewater. Recent developments also include in situ electrochemical SERS for rapid screening of opioid analogues. Collectively, these innovations underscore the global significance of SERS for rapid, non-destructive and highly specific forensic analysis.

Research from Nature Portfolio

Recent studies have demonstrated the feasibility of smartphone-based SERS for forensic drug classification by capturing two-dimensional Raman intensity maps with a CMOS sensor and periodic band-pass filters. A novel “spectral barcode” approach combined with convolutional neural networks achieved 99.0% accuracy in distinguishing major drug components and brand variants. Integration with conventional RGB imaging and image-recognition algorithms further enhances the robustness of on-site screening, pointing to a future in which ubiquitous consumer devices perform reliable, high-throughput forensic assays.

Research from all publishers

Investigations using commercial handheld Raman spectrometers have shown a 97.5% true positive rate in the detection of cocaine in seized samples, with limits of detection dependent on sample composition but remaining well below typical street-level concentrations. A comprehensive review of SERS-based illicit drug detection in biological fluids highlighted recent substrate innovations—such as fibre-enhanced platforms and self-assembled monolayers—that improve quantitative and qualitative performance in complex matrices. Meanwhile, an electrochemical-SERS method has been established for in situ preparation of active substrates and adsorption of fentanyl and its analogues, achieving low-nanogram-per-millilitre detection limits and selective identification of analogues in mixtures containing as little as 1% fentanyl by weight.

Surface-Enhanced Raman Spectroscopy Applications in Forensic Analysis publication trend

The graph below shows the total number of articles in surface-enhanced raman spectroscopy applications in forensic analysis across all publications each year (not limited to Nature Index journals).

Technical terms

Raman spectroscopy: A vibrational spectroscopic technique that probes molecular bonds by inelastic scattering of monochromatic light.

Surface-enhanced Raman spectroscopy (SERS): A method that enhances Raman scattering by placing analytes near plasmonic nanostructures.

Plasmonic substrate: A metallic nanostructured surface or nanoparticle ensemble that supports collective electron oscillations to amplify electromagnetic fields.

Chemometrics: Multivariate statistical and computational methods used to interpret complex spectral data.

Limit of detection (LOD): The lowest concentration of an analyte that can be reliably distinguished from background noise.

Electrochemical-SERS (EC-SERS): A variant of SERS in which an electrochemical step prepares or modifies the plasmonic substrate in situ for enhanced sensitivity.

Spectral barcode: A two-dimensional representation of Raman intensities across multiple wavelengths used as a unique fingerprint for classification.

References

1. Drug classification with a spectral barcode obtained with a smartphone Raman spectrometer. Nature Communications (2023).
2. Performance evaluation of handheld Raman spectroscopy for cocaine detection in forensic case samples. Drug Testing and Analysis (2021).
3. Recent Advances in the Use of Surface-Enhanced Raman Scattering for Illicit Drug Detection. Sensors (2022).
4. Forensic Identification of Fentanyl and its Analogs by Electrochemical-Surface Enhanced Raman Spectroscopy (EC-SERS) for the Screening of Seized Drugs of Abuse. Frontiers in Analytical Science (2022).