Extracts of 100 plant-like or resinous materials were analyzed for CBD, CBC, delta 9-THC, and CBN by GC using two different column packings and by GC-MS. Our independent identification of these cannabinoids confirmed those of other forensic science analysts who used microscopic examination, the Duquenois-Levine color test, and TLC for their analyses of the same samples. The identifications of cannabinoids by forensic acience analysts using TLC were corroborated by GC-MS analysis of hexane extracts of appropriate chromatogram spots.
The Swiss tests should not be used alone, she told the Virginia Department of Forensic Science board, because they can produce false positives.
In Florida, where the law recently changed to allow CBD with up to 0.3% THC, law enforcement agencies have been rushing to purchase the new kits. Waldheim said he’s now received orders from North Carolina, Texas and Tennessee, as well, and is in the process of creating a U.S. distribution center.
Speaking at a board meeting, Linda Jackson said her office ran extensive validation tests on the Swiss kits and recommends police officers use them in tandem with the former kits.
That’s welcome news to Herndon Police Chief Maggie DeBoard, who said changing CBD laws have made it difficult for officers to successfully crack down on illegal marijuana. In March, Virginia made it legal for hemp-derived CBD products to contain up to 0.3% THC, the chemical that can produce a high.
Solid reagent Fast blue B salt, (3,3′-dimethoxybiphenyl-4,4′-bisdiazonium chloride). Dilute Fast blue B salt, 1:100 with solid anhydrous sodium sulphate
Place about 1 mg resin or 2 mg herbal sample in a test tube with 100 ± 50 mg of the solid reagent. Add 1 ± 0.5 ml ethanol and heat to dissolve the solid. It is not necessary to heat longer than the time needed to dissolve the reagent, which, if unshaken, is usually when the solution comes to the boil, say 10 seconds. In the laboratory heat is most conveniently applied from a steam bath, but a match or cigarette lighter provides adequate heat for an analyst’s field kit. Without cooling, add 1 to 3 ml concentrated hydrochloric acid. If the acid is added dropwise, positive samples normally develop a strong violet colour during the addition. Allow up to a minute if needed for the colour to develop, add 1 to 3 ml chloroform, agitate the tube to mix and allow the phases to separate. A pink/mauve colour in the chloroform layer is a positive response.
Solid reagent – Powder and mix intimately 1 % metaldehyde in vanillin
(A) “Meta” Duquenois test
Where it is difficult to obtain pure ethanol, adequate results are obtained with industrial methylated spirit, and provided a control is carried out at the same time, even mineralised methylated spirit with added dyestuff can be used with care. If the hydrochloric acid used is weak, or has deteriorated through excessive exposure to the atmosphere, poor colour development will result. Apart from strong sulphuric acid (>50 %) no satisfactory substitute was found; no solid acid produced a colour. Substitution of piperonal for vanillin did not offer any advantage, the colour being a little slower to develop but of about the same intensity. The concentration of metaldehyde in vanillin is not critical and can be varied between 0.1 and 10 %, the best results being obtained at about 1%.
Low boiling petroleum ether (boiling range 40-60 °C) – PE
The rapid Duquenois test [ (2)] uses the same reagents and is preferred to the conventional version because of its speed and simplicity, viz: add 2 ml of the reagent directly to the suspect material in a test-tube (without any prior petroleum ether extraction stage) add 2ml concentrated hydrochloric acid, observe the colour transitions, add 1 to 2 ml chloroform, shake and observe the colour of the chloroform layer. This modification lacks specificity without the chloroform addition stage. It was initially considered for field use and in these early investigations it was noted that a direct substitution of metaldehyde for acetaldehyde improved the keeping qualities of the Duquenois reagent, and allowed a solid form to be kept indefinitely with the added advantages of increased sensitivity and speed of response. To distinguish this modification from the rapid and standard versions, the prefix “meta” is used. It is now used to the exclusion of the other two in this Laboratory and was only discarded as a potential field-test after the superiority of the Fast blue B salt method [ (3)] became apparent. These two new tests are described and discussed below.
2 dropping bottles
Place 1 mg of the suspect material on an absorbent paper, add one drop of petroleum ether, allow to soak into the paper and dry naturally. Remove the suspect material from the paper (tip into a test tube if the” meta” Duquenois test is to be applied subsequently), place about 0.1 mg of the solid reagent on the absorbent paper at the original site of the suspect material and add one drop of water to it. A red to violet colour develops as the water spot expands over the area originally covered by the petroleum ether spot. When dealing with powdery or sticky materials, it is necessary to use two thicknesses of absorbent paper and sufficient PE to moisten the lower paper, and to apply the test to the lower paper. If the PE solution is not filtered in this manner, most powders will leave enough residue on the paper to give sufficient water soluble material for a false positive.