Arsenic compounds in the edible red alga, Porphyra tenera, and in nori and yakinori, food items produced from red algae

Abstract

AbstractArsenic compounds were extracted with methanol/water (1:1, v/v) from freeze‐dried samples of the edible red alga, Porphyra tenera (asakusanori in Japanese), and also from nori and yakinori, food items produced from red algae. The extracts were analyzed by high‐performance liquid chromatography (HPLC) with an inductively coupled plasma mass spectrometer (ICPMS) serving as an arsenic‐specific detector. Two arsenic‐containing ribofuranosides were identified in all samples tigated, and they accounted for almost all the extractable arsenic (8.7–21 mg As Kg−1 dry sample) in each sample. A compound bearing a glycer‐ophosphoryl glycerol moiety was dominant in every sample. Arsenite, arsenate, methylarsonate, and dimethylarsinate were quantified by hydride generation and atomic absorption spectrometry. Arsenate and dimethylarsinate were detected in all samples at low levels (around 0.15 and 0.05 mg As Kg−1 dry sample, respectively). Arsenite was detected only in the unprocessed Porphyra tenera at 0.005 mg As Kg−1 dry sample. Methylarsonate was not found in any of the samples.