Chromatography Forum

Dear All,

Recently (last 1 year actually) I collected data for one of my experiment about the storage stability of pesticide residue in olive oil under our pre-selected storage condition.

This is the short description about the way I carried my experiment

2x20 vials of olive oil samples (5g each) were prepared from a stock of olive oil (500g) containing 0.25mg of pesticide of interest (Cypermethrin).
After this, all the samples were kept in freezer at -18 degree C (in dark).
At each sampling day (total 20 sampling days) , 2 vials were taken out from the freezer and the amount of cypermethrin was determined (with duplicate injections).

Now, I have two set of data namely set A and set B.

My questions are:
1. What should I do to determine whether the pesticide was degraded during the storage period? (In term of statistics or other ways)
2. How many replicates that normally needed for pesticide storage data?

Thanks

If over the 20 days, your pesticide levels dropped then surely it was because it was degrading. Plot a graph of Days vs Pesticide Level. I think it might be better to check your data in triplicates than duplicates. I am not an expert but these are just some suggestions.


Best Of Luck