Cannabinoids detection

Gustafson, R.A. et al., Urinary cannabinoid detection times after controlled oral administration of delta9-tetrahydrocannabinol to humans, Clin. Chem., 49(7), 1114-1124, 2003. 

The chromatograms of the E-III fraction which should contain the more polar acid metabolites, had too much interference from endogenous substances to allow cannabinoid detection. A comparison of the endogenous matrix levels of the hexane and ether extracts, expressed in terms of relative 215nm absorbance area in the cannabinoid elution region, is given in Table 3. 

Baumgartner et al." and Mieczkowski and NeweB" compared cannabinoid detection in urine and hair samples. They concluded that hair analysis and urinalysis were complementary rather than competing tests. Urinalysis provides short-term information of an individual s drug use, whereas long-term histories are accessible through hair analysis. Moreover, in contrast with qualitative information from urinalysis, hair analysis provides quantitative information on the severity and pattern of an individual s drug use. 

Some of the first synthetic cannabinoids detected in Spice were synthesized and named after John W. Huffman, a professor emeritus of organic chemistry... 

Fig. 1 Chromatograms of urine samples containing THC metabolites detection with fast blue salt RR (A) and fast blue salt B (B). Track Ai and B, metabolite-free urines tracks A,6 and B15 represent ca. 60 ng total cannabinoids per ml urine (determined by RIA).

Analytical Methods for Detection of A9-THC and Other Cannabinoids in Plants... 

Many methods for determination of cannabinoids in plant material have been developed. Commonly HPLC or GC is used, often in combination with mass spectrometry. Molecular techniques are also available to detect these compounds and will be discussed in this section. 

Whilst for the analysis of plant material for cannabinoids both GC and HPLC are commonly used, in analytical procedures the employment of GC-based methods prevails for human forensic samples. Nonetheless, the usage of HPLC becomes more and more of interest in this field especially in combination with MS [115-120]. Besides the usage of deuterated samples as internal standards Fisher et al. [121] describe the use of a dibrominated THC-COOH (see 7.5). The usage of Thermospray-MS and electrochemical detection provide good performance and can replace the still-used conventional UV detector. Another advantage in the employment of HPLC rather than GC could be the integration of SPE cartridges, which are needed for sample preparation in the HPLC-system. 

Most of the tests that were developed for detection of cannabinoids in plants have shown that antibodies are specific for the cannabinoid structure. Because of this specifity these tests can be extensively applied for the detection of cannabinoids and metabolites in human body fluids such as plasma, urine, and oral fluids. Many different kits based on these methods were developed and they are commercially available, for example Oratect, Branan or Uplink, and OraSure. We must consider, however, that no humans have the same metabolite profile in their blood and that cross-reactivity may always occur [122,123]. Nevertheless, these tests offer a simple way of excluding most of the suspicious samples, but the results still have to be confirmed with a second method such as GC-MS [124,125]. 

The best studied of the endocarmabinoids are anandamide (A -arachidonyl-ethanolamine, AEA)(1) and 2-arachidonylglycerol (2-AG)(2). Anandamide was first identified from porcine brain extracts by Devane and co-workers in 1992 [13], while 2-AG was first reported in 1995 to have been isolated from canine gut [14] and rat brain [15]. More recently, noladin ether (2-arachidonyl-glyceryl ether, 2-AGE)(3) [16], virodhamine (D-arachidonyl-ethanolamine)(4) [17] and A-arachidonyl-dopamine (NADA)(5) [18] were proposed as endogenous ligands for the cannabinoid receptors. In a subsequent publication, the authors failed to detect noladin ether in mammalian brains and questioned the relevance of this compound as an endocarmabinoid [19]. Anandamide, noladin ether and NADA have functional selectivity for CBi receptors, virodhamine is CB2 selective and 2-AG is essentially non-selective. 

Contrary to other studies, 6ACM and THC presented 100% removal in this study, but due to their low frequency of detection in raw wastewaters and then-absence in treated wastewaters (see Figs. 2 and 5). This fact also affects the overall satisfactory removal of opioids (88%) and cannabinoids (79%). However, removal of morphine, the opioid most frequently detected in wastewaters ranged between 46 and 100%, variability also observed by other authors. In the case of cannabinoids, removals reported are very diverse. The average poor removal observed for THC-COOH in the investigated WWTPs from the Ebro River basin (48%) results from occasionally higher concentrations of this analyte in treated wastewaters compared to raw wastewaters. This finding has also been reported in other studies [7, 19]. 

To find answers to these crucial questions and to establish if the occurrence of psychotropic substances in the atmospheric aerosols is just a curiosity or rather a potential problem for the community, a series of investigations have been carried out both in the laboratory and in the field. Dedicated procedures have been optimised, for instance, for cocaine and cannabinoids (see sections below), and the chemical stability of cocaine in airborne particulates and its partition between gas and aerosol phases were estimated, as well as its accumulation in fine rather than coarse particles. Furthermore, cocaine and cannabinoids concentrations have been measured in several cities over the world through field studies. After the first detection of cocaine in ambient air by Hannigan et al. [1] in Los Angeles, measurements were performed more extensively in Italy (for instance over 10 consecutive months in downtown Rome, or in 38 Italian localities) and Spain... 

As shown in Table 2, cocaine concentrations are detected in almost all the studies targeting psychoactive substances or drugs of abuse in the literature, with the exception of Algiers and Serbia, where cannabinoids were found whilst cocaine was not (Tables 3 and 4). In the literature, cannabinoid concentrations are either expressed as A -tetrahydrocannbinol (THC) or as the sum of cannabinol, cannabidiol and THC (known as CBs). 

Table 3 Airborne concentrations of THC and cannabinoids (CBs) detected around the world...

THC is lipid soluble and is released slowly from fatty tissue. This explains why cannabinoid metabolites may be detected for 3 to 10 days in occasional users and for many weeks in chronic... 

Some cannabinoids in human urine have been analyzed by fluorogenic labeling with DNS-C1 [139]. The labeled derivatives are separated by TLC. 0.5-ng amounts of the derivatives can be detected. 

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