2.4.3. Sample clean-up
The cartridges were conditioned using 2 ml of methanol and 2 ml of deionized
water, and then loaded with the organic phase pooled from tissue. Analytes were
eluted using 3 ml of n-hexane, and then the eluate was evaporated to dryness. The
dry extract was dissolved in hexane and spiked with internal standard (fenthion,
1 mg/ml). In the final step, 1 ml was injected into the GC/MS system.