I am operating Chemstation on OpenLabs with a Agilent 1220 Infinity II. My question revolves around the equation used to calculate sample potency based on the standard curve I have created. My procedure (standards used 1, 5, 10, 50, 100 µg/mL instead) is as follows https://www.agilent.com/cs/library/applications/application-dedicated-cannabinoid-potency-testing-5991-9285-en-us-agilent.pdf
My standard curve is seemingly fine, great r^2? However, I have a sample of known potency 25%, when I run it through based on my calibration curve I get 45% potency. I am wondering where this difference could be coming from? I know the calibration curve slope is to shallow for the equation to return a correct potency on known potency samples (my slope for THCA is around 6, while in the calibration results of the link above it is 24). I am wondering why mine differs so much?
There is a custom calculation at the end to get total potency = (THCA*0.877)+THC9
I have the ceramic homogenizers in the tube with the sample and methanol at step 1/2 of Sample preparation for flower.
My processing method: Curve Calculation "from average per level", RF definition "Response per amount", Concentration calculation amount * multipliers / dilution factors. (Multipliers = 20, 20. Dilution factors = 0.2, 10000). Based on the method linked above. There are no multipliers or dilution factors on the calibration curve injections.
If anyone has any insight or if there is further information I can provide I would be pleased to reply.
Thanks in advance.