Identification and quantification of seized illicit drugs using benchtop NMR with quantum mechanical spectral analysis

Simultaneous identification and quantification of illicit drugs can substantially reduce the reliance on multiple analytical instruments and lower operational costs. This study evaluates the capability of benchtop NMR spectroscopy for integrated qualitative and quantitative drug analysis. A 60 MHz benchtop NMR spectrometer was employed to examine blind and seized casework samples suspected to contain methamphetamine (MA) or 3,4-methylenedioxymethamphetamine (MDMA). Spectral data were processed using a novel peak-matching algorithm, followed by an approach based on Wasserstein distance and a quantum mechanical spectral analysis (QMSA) framework to enable simultaneous identification and quantification. The analytical performance of benchtop NMR was benchmarked against conventional techniques, with identification compared to FT-IR and GC–MS, and quantification compared to HPLC-UV and high-field NMR. The identification algorithm reliably identified the suspected drugs in all samples and detected associated adulterants in most cases. Quantitatively, for suspected drugs, the approach based on Wasserstein distance achieved a root mean square error (RMSE) of 3.8 mg analyte/100 mg sample and QMSA achieved 1.3, compared to 1.4 for HPLC-UV and 1.6 for high-field NMR. For seized samples, RMSE values relative to HPLC-UV were 3.8 for Wasserstein distance approach and 1.5 mg analyte/100 mg sample for QMSA. These results demonstrate that benchtop NMR can provide a rapid, cost-effective, and reliable analytical approach capable of simultaneous identification and quantification of analytes without the need for compound-specific calibration standards. This integrated approach demonstrates strong potential for forensic laboratories and harm-reduction centres conducting routine drug screening.