ORIGINAL PAPER Headspace sampling and detection of cocaine, MDMA, and marijuana via volatile markers in the presence of potential interferences by solid phase microextraction–ion mobility spectrometry (SPME-IMS) Hanh Lai & Inge Corbin & José R. Almirall Received: 26 April 2008 / Revised: 31 May 2008 / Accepted: 2 June 2008 / Published online: 5 July 2008 # Springer-Verlag 2008 Abstract The successful air sampling and detection of cocaine, methylenedioxymethylamphetamine (MDMA), and marijuana using SPME-IMS achieved by targeting their volatile markers (methyl benzoate, piperonal, and terpenes, respectively) is presented. Conventional methods of direct air sampling for drugs are ineffective because the parent compounds of these drugs have very low vapor pressures, making them unavailable for headspace sampling. Instead of targeting the parent drugs, IMS was set at the optimal operating conditions (determined in previous work) in order to detect their volatile chemical markers. SPME is an effective and rapid air sampling technique for the preconcentration of analytes which is especially useful in confined spaces such as cargo containers, where the volatile marker compounds of drugs can be found in sufficient concentrations. By sampling the air using a 100 μm polydimethyl siloxane (PDMS) SPME fiber for as little as one minute, enough mass of the targeted volatile markers in the headspace of a quart-sized metal paint can (gallon, ∼1101 cm 3 ) which contained sub-gram quantities of the drug samples was recovered for IMS detection. Addi- tionally, several potentially interfering compounds found in goods commonly shipped in cargo containers were tested individually as well as in mixtures with the drugs. No peak interferences were observed for MDMA or marijuana, and minimal peak interferences were found for cocaine. Keywords Illicit drugs . Cocaine . MDMA . Marijuana . Solid phase microextraction . Ion mobility spectrometry Introduction Screening commercial cargo for illicit substances without impeding the throughput of the customs processing of these containers is a challenging task for the US Customs and Border Protection, due to the high volume and variety of cargo entering the United States through border crossings at land, seaports and airports every day [1, 2]. Inspection officers have only 30–45 seconds to decide whether a container should be inspected further [3]. A few minutes of delay can cause inconvenience and additional cost to the import/export industry [1, 2]. While the cost of a false positive alarm is calculated in terms of time and money, the consequence of not detecting a real security threat (false negative) can cause severe damage to the economy and to society. Therefore, high-throughput inspection systems that can rapidly screen and accurately identify suspicious cargo are required [1, 4]. At the current time, there is no “silver bullet” contraband detection technology [4]. Both bulk and trace detection systems are employed at checkpoints to complement one another during the screening process in order avoid having to manually unload and examine every container [1, 3]. The two trace detection systems that are most commonly employed at US checkpoints are canines and ion mobility spectrometry (IMS) [5–8]. Canines are generally reliable but can only work limited hours, they are labor-intensive to train and to maintain properly, and are subject to handler bias [9]. The actual reliability of canine detection teams is determined by the maintenance system used by the individual handlers or agencies employing them [8, 9]. Anal Bioanal Chem (2008) 392:105–113 DOI 10.1007/s00216-008-2229-z H. Lai : J. R. Almirall (*) Department of Chemistry and Biochemistry, International Forensic Research Institute, Florida International University, 11200 SW 8th St. CP 316, Miami, FL 33199, USA e-mail: almirall@fiu.edu I. Corbin Miami-Dade Police Department, Crime Laboratory Bureau, Miami, FL 33172, USA