Dokha brand differentiation by elemental analysis measured by inductively coupled plasma-mass spectrometry.

Dokha is a tobacco product commonly used in Middle Eastern and Northern African regions. It is available in three blends purportedly corresponding to the degree of "buzz" experienced by the user. The "buzz" has been linked in part to nicotine levels, which are higher than those found in cigarettes and is believed to be the reason dokha is abused as a "legal high." There have been reports of seizure activity from dokha users, and elevated concentrations of toxic metals have been measured in dokha tobacco. The purpose of this work was to determine whether we could use dokha's elemental content, measured by inductively coupled plasma-mass spectrometry, to link dokha back to its brand. This could aid investigators in identifying brands and/or distribution routes in the case of adverse effects resulting from dokha use. We measured the concentrations of Mg, K, Mn, Ni, Cu, Rb, Sr, and Ba in Medwakh, Nirvana, Scorpion, Enjoy, Kingdom, and Iconic dokha brands. Analysis of variance revealed statistical differences in concentrations of elements among groups. Discriminant function analysis (using leave-one-out classification) was 58.3% successful at differentiating brands. Enjoy dokha was the most, and Kingdom dokha the least, correctly classified among groups. Attempts to further link dokha blends back to light, medium, and heavy blends were less successful. These results indicate potential for using elemental content to discriminate among dokha brands. Our data may also help to understand the degree of additional processing and/or adulteration of dokha products available to users in the United States.

Determining the Method Threshold of Identification via Gas Chromatography-Mass Spectrometry of Weathered Gasoline Extracted from Burnt Nylon Carpet.

The Organization of Scientific Area Committees defines threshold of identification as the minimum concentration of ignitable liquid identifiable from gas chromatographic-mass spectrometry data using accepted pattern identification criteria. We propose a method for determining this threshold for gasoline based on base peak to qualifier ratios of six compounds. The ion ratios were established for each compound in the neat gasoline. These ratios were then compared to those obtained for gasoline and 98% weathered gasoline both spiked onto burnt nylon carpet at 20 ppt down 0.50 ppt, and recovered from the carpet using headspace extraction (ASTM 1412). Identification was confirmed if the compounds' ion ratios fell within ±25% of that in the neat sample. We found that ion ratios for all samples were acceptable for six compounds at 1.60 and 0.80 ppt for extracted neat and extracted 98% weathered gasoline, respectively, illustrating potential for incorporating into Quality Assurance Programs.