PSYCHOTROPIC SUBSTANCES IN URBAN AIRBORNE PARTICULATES

Psychotropic compounds, such as caffeine and nicotine, can exist in air as a result of their release in tobacco smoke or when certain drugs or essences are inhaled as vapors. These psychotropic substances belong to various classes of organic compounds with different physico chemical properties and different routes of release into the environment, so they may exist in the gaseous or asparticulates and as native compounds or derivatives. For instance, nicotine is mostly gaseous when it is a free base, but combines with tobacco smoke particles when in acidic form (Liang and Pankow, 1996). Cocaine and heroin in the atmosphere presumably exist mainly as solid particulates (Dindal et al., 2000 Cecinato and Balducci, 2007). 

These substances may be hydrophilic or hydrophobic, depending on their polarity and acid properties. Similar to nicotine, caffeine is fairly water soluble (22 g/L at 25°C and 180 g/L at 80°C). Cocaine chlorhydiate is hundreds of times more soluble than its base (1800 and 1.7 g/L), and heroin is poorly soluble in water (0.6 g/L). Vapor pressures of cannabinoids mean they can exist only when particle associated (McPartland and Russo, 2001) and their solubility in water is low (less than 2 mg/L for A -tetraltydrocannabinol (THC) Jarho etal., 1998). Moreover, these compounds decompose so rapidly in the environment that they can be detected only in trace amounts (a few pigogram per cubic meter), in spite of the fact that marijuana is the most abused drag worldwide. 

Dedicated instruments and procedures exist for the detection and quantification of illicit substances in vapors of ambient or artificial atmospheres (Ziegler et al., 1996 Stubbs et al., 2003), but because of their low sensitivity they need high bindens of the compounds in air or require derivatization, e.g., with methylbenzoate 

Illicit Drugs in the Environment Occurrence, Analysis, and Fate Using Mass Spectrometry, Edited by Sara Castiglioni, Ettore Zuccato, and Roberto Fanelb Copyright 2011 John Wiley Sons, Inc. 

The first observation of illicit drugs in the atmosphere was unexpected and occurred in a study with quite different goals. Thus, a preliminary objective of a subsequent study was to confirm the presence of these substances in air. Afterward, dedicated procedures were optimized to monitor psychotropic substances and drug residues in air with good precision and accuracy. The determination of psychotropic compounds in air is quite complex. Both air and airborne particles comprise thousands of 

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