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A Raman spectroscopy method for determining the drug content of street samples of amphetamine was developed by dissolving samples in an acidic solution containing an internal standard (sodium dihydrogen phosphate). The Raman spectra of the samples were measured with a CDD-Raman spectrometer. Two Raman quantification methods were used: (1) relative peak heights of characteristic signals of the amphetamine and the internal standard; and (2) multivariate calibration by partial least squares (PLS) based on second derivative of the spectra. For the determination of the peak height ratio, the spectra were baseline corrected and the peak height ratio (h(amphetamine at 994 cm(-1) )/h(internal standard at 880 cm(-1) )) was calculated. For the PLS analysis, the wave number interval of 1300-630 cm(-1) (348 data points) was chosen. No manual baseline correction was performed, but the spectra were differentiated twice to obtain their second derivatives, which were further analyzed. The Raman results were well in line with validated reference LC results when the Raman samples were analyzed within 2 h after dissolution. The present results clearly show that Raman spectroscopy is a good tool for rapid (acquisition time 1 min) and accurate quantitative analysis of street samples that contain illicit drugs and unknown adulterants and impurities.

A novel approach was used to analyze street drugs in seized material without primary reference standards. Identification was performed by liquid chromatography/time-of-flight mass spectrometry (LC/TOFMS), essentially based on accurate mass determination using a target library of 735 exact monoisotopic masses. Quantification was carried out by liquid chromatography/chemiluminescence nitrogen detection (LC/CLND) with a single secondary standard (caffeine), utilizing the detector's equimolar response to nitrogen. Sample preparation comprised dilution, first with methanol and further with the LC mobile phase. Altogether 21 seized drug samples were analyzed blind by the present method, and results were compared to accredited reference methods utilizing identification by gas chromatography/mass spectrometry and quantification by gas chromatography or liquid chromatography. The 31 drug findings by LC/TOFMS comprised 19 different drugs-of-abuse, byproducts, and adulterants, including amphetamine and tryptamine designer drugs, with one unresolved pair of compounds having an identical mass. By the reference methods, 27 findings could be confirmed, and among the four unconfirmed findings, only 1 apparent false positive was found. In the quantitative analysis of 11 amphetamine, heroin, and cocaine findings, mean relative difference between the results of LC/CLND and the reference methods was 11% (range 4.2-21%), without any observable bias. Mean relative standard deviation for three parallel LC/CLND results was 6%. Results suggest that the present combination of LC/TOFMS and LC/CLND offers a simple solution for the analysis of scheduled and designer drugs in seized material, independent of the availability of primary reference standards.

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