Abstract
Background: Seaweed and seafoodoften contain both inorganic and organic arsenic compounds showing distinct toxicities. Speciation must be taken into account when determining the concentrations of arsenic compounds and how they relate to overall toxicity. Objective: An analytical method for the quantitation of inorganicarsenic was validated in seaweed and seafood. Methods: Food samples were heated at 100°C in 0.3 mol/L nitric acid. Arsenic speciation was quantitatively determined by LC-inductively coupled plasma-MS (LC-ICP-MS) using an octadecilsilane (ODS) column with a mobile phase containing an ion-pair reagent. Results: Limits of detection (0.0023–0.012 mg/kg), LOQ (0.0077–0.042 mg/kg), repeatability (3.0–7.4%), intermediate precision (4.4–7.4%), and trueness (recoveries 94–107%) of the proposed method were satisfactory for inorganic arsenicin seaweed and seafood. Inorganic arsenic was detected in almost all the evaluated dried seaweed products, the Japanese oyster, nam pla, oyster sauce, and the intestinal organs of seafood. Conclusions: Among the dried seaweed products, significant inorganic arsenic was detected in the brown algae akamoku, hijiki, and mozuku. The small amounts of inorganic arsenic detected in nam pla and oyster sauce likely derive from the internal organs of the raw seafood used in their preparation. Highlights: Arsenic speciation in seaweed and seafood was measured by LC-ICP-MS using an ODS column with a mobile phase containing an ion-pair reagent. Among the dried seaweed products, brown algae akamoku, hijiki, and mozuku contained significantly high levels of inorganic arsenic. The intestinal organs of oyster, sardine, and scallop contained higher arsenic levels than the muscles.