The standards and cannabinoids of interest to be analyzed are THC, THC-A, CBD, and CBD-A. These can all be obtained from Sigma-Aldrich, under the term 'analytical sample', and of the names Δ9-Tetrahydrocannabinol solution, Delta9-Tetrahydrocannabinolic acid A solution, Cannabidiol solution, and Cannabidiolic acid solution.

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Specific terpenes to be analyzed have not yet been determined. There are samples available for purchase from Sigma-Aldrich, as to be expected. A list of standards can be found here (Page 8) and below. A list of various phytocompounds and their mass analyses can be found here (Table 2). 

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In terms of pesticides, a list of certified reference materials can be found below, linking to page 13 of Sigma-Aldirch's Cannabis Testing PDF. Testing for all of these is ideal, albeit not necessary. Exact requirements will be elucidated in the future, before testing. 

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The law currently reads as follows:

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(4) For purposes of the pesticide chemical residue test, a marijuana sample shall be deemed to have passed if it satisfies the most stringent acceptable standard for a pesticide chemical residue in any food item as set forth in Subpart C of the federal Environmental Protection Agency’s regulations for Tolerances and Exemptions for Pesticide Chemical Residues in Food, 40 CFR 180.

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This leads to a list of approximately 405 different pesticides, which would be unreasonable to test for, broadly. The solution is to identify the most common pesticides being applied to C. sativa hemp cultivars and to then test the products for that. 

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Standard sample preparation:

• Create a standard of 100ng/mL of CBD, CBDA, THC, and THCA in dilution solvent​

  • Dilution Solvent: 0.005% formic acid, 5% water, 95% methanol

  • CBD and THC stock solutions in MeOH should be stored at -20​℃ until use, then thawed at ~20℃

  • CBDA and THCA stock solutions in MeOH should be stored at -80℃ until use, then thawed at ~20℃

• Create an internal standard from THC-d3, CBD-d3, and THCCOOH-d3

  • The concentration should be 10ng/mL of each reference analyte​

  • All stock solutions for the internal standard (in MeOH) should be stored at -20℃ until use, then thawed at ~20℃

  • THC-d3 and CBD-d3 should be used as internal standards for THC and CBD respectively

  • THCCOOH-d3 should be used as an internal standard for THCA and CBDA

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Calibration curve

• Serial dilution of stock solution

  • Stock solution - 5​0ng/mL each of CBD, THC, CBDA, THCA  diluted in a 10ng/mL THC-d3, CBD-d3 and THCCOOH-d3 solution to:

    • In ng/mL: 50, 25, 12.5, 6.25, 3.12, 1.56, 0.78, 0.39 and 0.19​

      • Creates constant concentration of THC-d3, CBD-d3 and THCCOOH-d3 in each solution​ (Internal Standard)

  • Peak area ratio of analytes and corresponding IS vs concentration fit with a weighted quadratic or linear curve in Analyst software

  • Quality control samples can be used (MCT oil or olive oil - whatever extract oil applicable to CBD oil being analyzed) 

    • 200ng/mL, 50ng/mL, 5ng/mL and 0.5ng/mL for every batch​

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