dilution factor

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

Parents Reply
  • if i remove 2ml from the 20ml solution, isnt that the same concentration as the remaining 18ml? assuming proper homogenisation both will have 50mg/ml of gummy

    pardon the ignorance, but doesnt dilution usually involve reducing the concentration of an analyte in solution(mg/ml), not just the volume (ml)? for example if i used the 2ml and brought up to 20ml,  that would be x10 dilution? that is generally how i perform dilutions during sample prep. or have i being doing this the wrong way

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