Journal of Planar Chromatography 27 (2014) 6, 477–479 DOI: 10.1556/JPC.27.2014.6.13 477 0933-4173/$ 20.00 © Akadémiai Kiadó, Budapest 1 Introduction Dimethyltryptamine (DMT) is an endogenous hallucinogen with traditional use as a ceremony in the orally active prepara- tion of Ayahuasca, a hallucinogenic beverage used by indige- nous communities in the Amazon. Although the religious use of Ayahuasca has been studied extensively, very little is known about the recreational use of DMT [1]. Recently, many people have shown prominent attention in traditional indigenous prac- tices and popular medicine, involving the ingestion of natural psychotropic drugs [2]. The consumption of Ayahuasca is increasing worldwide due to the expansion of syncretic religions founded in the north of Brazil in the first half of the twentieth century, such as Santo Daime. This product contains N,N- dimethyltryptamine which needs coadministration of naturally occurring monoamine oxidase inhibitors, for example, β-carbo- line derivatives, in order to induce its psychoactive effects in humans, so this substance is required by users of DMT to be effective orally [3]. Dimethyltryptamine dose-dependently ele- vated blood pressure, heart rate, pupil diameter, and rectal tem- perature, in addition to elevating blood concentrations of b- endorphin, corticotrophins, cortisol, and prolactin. Growth hor- mone blood levels rose equally in response to all doses of DMT, even though melatonin levels are unaffected [4]. While previous studies of DMT use had examined Ayahuasca use exclusively [5], several studies had demonstrated the ubiquity of smoking as the most prevalent route of administration among recreational DMT users. A wide spread of analytical methods had been developed in order to establish the composition of Ayahuasca, but there is not much information available about the analysis of DMT in street samples. Due to this reason, we implemented a fast and reliable method for the determination of DMT by HPTLC that offers many advantages such as rapidness, low cost, accuracy, and precision. The use of validated methods is significant for an analytical laboratory to show its qualification and capabilities [6]. In this scenario, we developed and validat- ed a rapid and simple method for the detection and quantitation of DMT in illicit powder samples. Besides validation parame- ters, the uncertainty of the method was also evaluated [7]. 2 Experimental 2.1 Chemicals and Reagents N,N-Dimethyltryptamine was generously provided by Drug Enforcement Administration, Washington DC. Methanol and conc. ammonia were of analytical grade, purchased from Merck, Darmstadt, Germany. 2.2 Chromatography The analysis was performed on 10 × 10 cm precoated silica gel F 254 plates (Merck, Darmstadt, Germany), previously activated at 80°C for 20 min. One microliter of standards and samples was applied in bands of 4 mm with an ATS 4 automatic TLC sampler, using a spray band technique; the first application x axis was 10 mm and y axis was 8.0 mm, and the distance between the tracks was 4.2 mm. Plates were developed with an automatic developing chamber ADC-2 without saturation to a distance of 70 mm, with methanol–ammonia 100:1.5 as the mobile phase (10 mL, freshly prepared) and drying time of 2.0 min; the spots were scanned with a TLC Scanner 4 densitometer by absorbance at 220 nm. Spectra of each peak were recorded in the range of 190–400 nm on all detected peaks mode; slit dimension, 4.00 × 0.30 mm; scanning speed, 20 nm s −1 ; data resolution, 100 µm step −1 ; reference spectrum, x = 10.0 m and, y = 5.0 mm. All processes were controlled with the software winCATS Planar Chromatography Manager, version 1.4.7 (CAMAG, Muttenz, Switzerland). 3 Results and Discussion The proposed method was validated according to parameters of the International Conference on Harmonization (ICH) guide- Thin-Layer Chromatography Method for the Detection of N,N-Dimethyltryptamine in Seized Street Samples Boris Duffau*, Sonia Rojas, Sebastian Jofre, Marcelo Kogan, Iván Triviño, and Paula Fuentes Key Words High-performance thin-layer chromatography Dimethyltryptamine Hallucinogens Uncertainty B. Duffau, S. Rojas, S. Jofre, P. Fuentes, and I. Triviño, Drug Analysis Section, Institute of Public Health of Chile, Chile; and M. Kogan, Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Chile. E-mail: bduffau@gmail.com