Preliminary results on direct quantitative determination of cocaine in impregnated materials by infrared spectroscopy

Partial least squares models were built for the direct determination of cocaine in seized impregnated smuggled materials. Measurements are based on the attenuated total reflectance middle infrared spectra (ATR-MIR) and diffuse reflectance spectra in the near range (DR-NIR) obtained directly from the surface of the impregnated materials. The aforementioned procedures offer fast, cheap and environmentally friendly green alternatives to the reference method based on the extraction of the drug and its quantification by gas chromatography. Additionally it has been verified that results found are statistically comparable with those obtained by the reference method with root mean square errors of prediction (RMSEP) of 0.60% w/w and 0.88% w/w for MIR and NIR methods, and ratio of performance to deviation (RPD) values of 13.20 and 7.54, respectively. Examples of application for the quantification of cocaine in impregnated clothes, pulp paper and foam have been also provided.