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SI traceable determination of arsenic species in kelp (Thallus laminariae)



Lee L. Yu, Rolf L. Zeisler, Rachel C. Stanoyevitch


Kelp is a dietary supplement that contains significant amount of arsenic. Accurate assessment of dietary safety of kelp requires the determination of the arsenic species therein. A procedure was developed to extract the hydrophilic fraction of arsenicals reproducibly from a candidate standard reference material (SRM) 3232 Kelp in development at the National Institute of Standards and Technology (NIST). Arsenosugars and dimethylarsinic acid (DMA) that accounted for > 97% arsenic in the extract were separated into fractions that were subsequently determined using instrumental neutron activation analysis (INAA). Arsenosugar As(328) was determined by INAA for the first time after the fraction was isolated by cation exchange. The minor components of arsenic species in the kelp extract were determined by LC-ICP-MS. The LC-ICP-MS results of arsenosugar As(328) and DMA at 1.14 mg/kg ± 0.02 mg/kg and 0.484 mg/kg ± 0.024 mg/kg were in good agreement with those determined by cation exchange and anion exchange LC-INAA at 1.16 mg/kg ± 0.25 mg/kg and 0.50 mg/kg ± 0.10 mg/kg, respectively. The most toxic minor species AsIII and AsV were found to be
Analytical Methods


arsenic species, arsenosugar, extraction, LC, INAA, ICP-MS


Yu, L. , Zeisler, R. and Stanoyevitch, R. (2017), SI traceable determination of arsenic species in kelp (Thallus laminariae), Analytical Methods (Accessed June 18, 2024)


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Created June 26, 2017, Updated August 1, 2017