2.3. Extraction
Portions (ca 0.5 g weighed to 0.1 mg) of sample (beetroot spiked with 100 μg As AB by adding 100 μl of a 1000 mg As L− 1 AB solution to the dry powder before adding the extraction solvent; freeze-dried fish samples; CRM Dorm-2; or CRM Dorm-2 spiked with 2.5 mg GB by adding 2.5 mL of a 1000 mg L− 1 GB solution) were placed in 50 mL polypropylene tubes and extracted in 10 mL of water/methanol (1 + 1, v/v) overnight on a mechanical rotation device.