Arsenic species extraction of biological marine samples (Periwinkles, Littorina littorea) from a highly contaminated site

► Three two-step arsenic extraction methods compared for contaminated marine tissue. ► Comparable amounts extracted but methanol required to extract tetramethylarsonium ion. ► Optimized method is a 1:1 methanol-water extraction followed by a 2% HNO3 extraction.