Sim et al. 2024 — HPLC-ICP-MS method for inorganic arsenic in seaweed, grain, and novel food matrices
This paper develops and validates an optimized HPLC-ICP-MS method for iAs determination in a range of food matrices including seaweed, rice, grass silage, and insect proteins, using a design of experiments (DoE) approach to optimize chromatographic conditions. The method is validated against certified reference material (hijiki certified reference material) achieving 99±9% recovery for iAs. The paper also reports iAs concentrations in the tested matrices, establishing that Laminaria digitata can have iAs comprising more than 50% of total arsenic in some samples, with regulatory implications under the EU maximum level for iAs in seaweed.
Key numbers
- Certified reference material recovery: 99±9% for iAs in hijiki seaweed (excellent method validation)
- Laminaria digitata iAs: up to >50% of total As in some samples; specific concentration values reported (see source tables)
- Fucus spp.: lower iAs/tAs ratio than Laminaria
- Saccharina latissima: iAs lower than Laminaria, consistent with brown macroalgae literature
- Asparagopsis taxiformis: contains organoarsenic brominated compounds that may interfere with standard iAs methods; this paper addresses that interference
- Porphyra spp. (nori): low iAs, predominantly arsenosugars
- Rice: method validated and suitable for iAs determination in rice; values consistent with published literature
- Insect proteins: novel application; iAs present at trace levels in insect-derived proteins tested
- Grass silage: included as an animal feed matrix; iAs measurable with the method
- EU regulatory context: EU Regulation 2023/915 sets maximum levels for iAs in specific seaweed species (e.g., Laminaria digitata, hijiki); this method is designed to support compliance testing
Methods (brief)
HPLC-ICP-MS with anion exchange column (Hamilton PRP-X100 or equivalent); mobile phase optimization by DoE (Box-Behnken design) varying pH, buffer concentration, and methanol percentage; LOD and LOQ for iAs determined; extraction by dilute HNO3 microwave-assisted digestion; certified reference material (NIES CRM No. 18 hijiki) used for method validation. Total As measured by ICP-MS without chromatography for comparison.
Implications
Certification: This is a directly applicable methods reference for iAs testing in seaweed and novel protein ingredients. The DoE-optimized method achieves excellent recovery and is validated against a certified reference. The EU regulatory context (Regulation 2023/915 iAs limits in seaweed) is explicitly addressed.
Courses: Exemplary paper for teaching HPLC-ICP-MS speciation methodology; also demonstrates DoE optimization approach for chromatographic method development.
App: Seaweed ingredients have complex arsenic speciation; iAs fraction can be >50% in Laminaria. Total As alone is insufficient for risk characterization in seaweed-derived ingredients.
Microbiome: Not applicable.