dilution factor

Question

Hello all, 
 
 I need some help understanding the agilent application note: Quantification of THC and CBD in Gummies and Hard Candies, specifically where the dilution factor is calculated 
 The SOP states: 
 1g gummy into 10ml water, then homogenise 
 add 10ml ACN to solution, homogenise 
 add quechers salt, shake + centrifuge 
 top 10ml ACN layer contains analytes 
 remove 2ml of the supernatant. 
 filter into sample vial 
 
 when i use x10 DF factor i am getting really high numbers which dont add up. Can anyone explain where the DF x10 comes from? I emailed one of paper authors and he just repeats that its x10. his reply was " You have a good question. The dilution is indeed 10X because you finish in 10 ml acetonitrile. In other words, you go from 20ml to 10 ml." but surely going from 20ml to 10ml, is a dilution factor of 0.5 
 
 im really confused, please help. i typicall use final-volume/initial-volume (or aliquot) to determine DF which seems to work, except in this example 
 
 Tan

Dr. Know · Accepted Answer

True, you will have a ca. 10 mL supernatant layer of ACN, where you take 2 mL from, which is a 1:5 ratio. Just ignore the DL in the text, it changes with adding standards or using different volumes of solvents. Again, be sure about the absolute amounts of the sample and what you analyze for your calculations. I will contact the author to remove the sentence from the application note.

Tannabis · Answer

Thanks. That being said, in my opinion the sample NEEDS dilution, maybe not x10 but def some. 
 I have THC and CBN calibrated from 1ug/ml -200ug/ml and when i perform the prep as stated my results is way beyond the calibration curve. I was going to start diluting this. 
 
 yes, thanks I will be sure to take care to make sure the amounts are correct. thanks for the help

Dr. Know · Answer

Step 3 adds the first 10 mL ACN/NH3 - 1 g in 10 mL Step 5 adds another 10 mL ACN/NH3 - 1 g in 20 mL 
 Step 10 you take 2 mL out of 20 mL, therefore the DL is 10 = 2/20

dilution factor

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