Hunting for illicit psychoactive substances and precursors: A multivariate approach

A significant raise in the use of illicit psychoactive substances has been reported in the last decade. This trend is probably due, especially in the case of amphetamine-type stimulants (ATS), to the fact that they are the easily synthesized. Globalization offers new ways of procuring the precursors of these substances (e.g. online) and helps cover the increasing production needs of clandestine laboratories. Hence, law enforcement authorities need new analytical instruments enabling an efficient and fast detection of these controlled substances for border control (customs) and police operations. We are presenting a chemometrical application designed to perform the automated recognition of ephedrines based on their vibrational absorptions. The spectra are recorded, with a new portable quantum cascade laser spectrometer, between 1405 and 1150 cm
^-1
(QCL UT8). The effect of spectra preprocessing with a feature weight we on the classification accuracy is discussed in detail.