Arsenic Species Determination in Seaweeds by Ion Chromatography–Inductively Coupled Plasma Mass Spectrometry

In this research, the most common arsenic species in seaweeds from Ho Chi Minh City (Vietnam) were determined using ion chromatography-tandem inductively coupled plasma mass spectrometry. An optimized extraction procedure was established, involving a 20 mL MeOH : H₂O (1 : 1, v/v) solution at 50°C for 10 min. Chromatographic separation of all the species was achieved in less than 7 min in gradient elution mode using an anion exchange column AS7, and the mobile phase consisted of 300 mM (NH₄)₂CO₃ and 3% MeOH at pH 10.3. The linear range for each arsenic species was from 0.1 to 100 µg/L. The method detection limits for arsenobetaine, dimethylarsinic acid, As(III), monomethylarsonic acid, and As(V) were 21.19, 4.76, 4.29, 2.78, and 2.28 µg/kg, respectively, and the method quantification limits were 100, 15.86, 14.31, and 9.27, 7.62 µg/kg, respectively. The method was validated for accuracy, precision, and specificity. Analysis of 15 seaweed samples revealed the presence of As(III) in some samples, while As(V) was not detected. This study presents a novel method for arsenic determination and provides valuable insights into arsenic levels in seaweed. The developed method offers a valuable tool for assessing arsenic contamination in marine ecosystems and understanding its potential risks to human health.