Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Will This Work?

Posts: 23
Registered: 12-1-2015
Location: Tampa, FL
Member Is Offline

Mood: No Mood

[*] posted on 17-2-2015 at 22:16
Will This Work?

Please don't laugh at me. I'm not used to being a real chemist.

I need to test marijuana for active ingredient (CBD, CBN, THC, THCA, etc.) The HPLC machine has a PDA detector. The column I will be using is a 250x4mm RP-8 (5 micrometer). Mobile phase is acetonitrile:water (8:2). The method for my coworkers is as follows:

Fold a KIMWIPE half-way. Place it on top of the analytical balance. Push the “tare” button on the analytical balance. Make sure both doors and the ceiling to the analytical balance are shut before hitting the “tare” button. The analytical balance should then read 0g. Using the analytical balance, weigh out 500mg of dry cannabis by placing it on the KIMWIPE. 500mg will read 0.5g on the analytical balance. Make a 5mL 9:1 methanol:chloroform mixture. To do this, pour 4.5mL methanol in the graduated cylinder using the eye dropper, and pour it into a separate beaker. Then pour 0.5mL chloroform into the graduated cylinder using the eye dropper, and pour that into the same beaker. Mix the contents of the beaker using the stirring rod. Pour the 0.5mg of dry cannabis into a 50mL centrifuge tube, and pour the 9:1 mixture into the tube. Vortex the contents of the centrifuge tube for 10sec by pressing the pointed tip of the tube on the center of the circular vortex rubber. Place the centrifuge tube in the ultrasonic bath for 15min, but remember to vortex for 10sec after every 5min, 10min, and 15min of ultrasonification. Place the centrifuge tube in the centrifuge machine, and be sure to balance it out by placing another centrifuge tube filled with water up to the same volume 180 degrees apart. Allow centrifugation to run for 1 minute at X RPM. Remove the centrifuge tube and pour the liquid contents into a HPLC vial.

Then I have directions for making the standards for the machine.

Now I also need to test for pesticides. The machine we have is just an HPLC with an MS pump. However, most methods I read online are HPLC-MS or GC-MS. But according to this site, they just used an HPLC to test for pesticides -

Can I use QuEChERS extraction method, and use the same machine but different column for pesticide testing?

View user's profile View All Posts By User

  Go To Top