How do you extract atrazine from food samples?

Atrazine is positively charged under acidic conditions. You can use Strata X-C for its extraction from vegetables. Here is a starting protocol you can follow.

Sample pretreatment:
Homogenize 0.5g vegetable sample in 10 mL of 0.1N HCl. Centrifuge and collect supernatant for SPE

To a 200 mg Strata-X-C cartridge,
Condition with 2 mL Methanol
Equilibrate with 2 mL 0.1N HCl
Load: pretreated sample
Wash 1: 3 mL 0.1N HCl
Wash 2: 3 mL Methanol
Dry: 5 minutes under full vacuum
Elute with 3 mL 5 % NH4OH in Methanol (v/v)

Depending on the vegetable sample, you may need to scale down on loading as some vegetables are rich in pigment or fat. If there is breakthrough during loading, you can scale down the amount of sample loaded. Please make sure the load and wash fractions are collected and analyzed to help monitor analyte movement.