They are ane app note about that?
Can I use EMR-LIPID in cocoa beans for GC-MSMS analysis of pesticides? Yes
What is the amount of sample to weigh to extract with acetonitrile?
I assume the cocoa beans are dried matrix. For dried matrix, the sample size is typically 2 g. You can just use the QuEChERS method to extract sample. Basically 2 g of sample + 10 mL of water, incubate for 10-15 mins, and then extract with ACN (or acidified ACN), and then add QuECheRS salts for salt partition. Depending on what official QuEChERS method to follow, adjust the solvent volume and salt packet.
Is it necessary to add water to the sample before doing the extraction with acetonitrile?
Water should be added after QuEChERS extraction, not before extraction. Basically after centrifuging, transfer the upper supernatant and mix with 20% of water, then load on Captiva EMR cartridge for cleanup.
Also for GC/MS/MS analysis, it’s important to remove water after EMR cleanup. For multiclass pesticides analysis, we usually recommend MgSO4 drying after EMR cleanup. Basically, add a pouch of EMR drying salt (~3.5 g of anhydrous MgSO4) to 5 mL of EMR eluent. Vortex thoroughly and centrifuge. The supernatant can be run on GC/MS/MS directly.