Infrared detection of cocaine and street cocaine in saliva with a one-step extraction
We present a novel approach for the detection of cocaine in saliva using infrared attenuated total reflection spectroscopy combined with a simple one-step extraction. We demonstrate the performance of this technique with saliva collected from several test persons, spiked with cocaine and street cocaine after sampling. The high efficiency of the extraction yields a limit of detection (LOD) of ∼1 μg cocaine per ml of saliva. A further reduction of the LOD is easily achieved by pre-concentration enabling a limit of detection of a few 100 ng ml−1 of cocaine in saliva. The technique represents an important step towards a compact, easy-to-use, portable, quick and semi-quantitative screening device for on-road-side tests. The extraction method is also applicable to sample preparation for other optical sensor schemes.