Arsenic species and their transformation pathways in marine plants. Usefulness of advanced hyphenated techniques HPLC/ICP-MS and UPLC/ESI-MS/MS in arsenic species analysis

Overview

Lorenc and colleagues developed and validated a combined HPLC/ICP-MS and UPLC/ESI-MS/MS workflow for arsenic in algae products. The occurrence-relevant data are the total arsenic and arsenic-speciation values in Table 2 for five algae/seaweed materials, including a commercial cooked/dried hijiki product, nori sheets, serrated wrack, and two reference materials. Unknown arsenic and arsenosugar species are kept separate from inorganic arsenic.

Key numbers

Table 2 reports total arsenic before extraction as mg kg-1 (c ± SD) and extracted/speciated arsenic as mg kg-1 (c ± U, k = 2). No unit conversion was performed.

Sample	Native tAs	Extraction	Extracted tAs	AsB	As(III)	DMA	As(V)	uAs
Sample 1, NMIJ CRM 7405-a Hijiki	34.38 ± 0.99	Water, UAE	17.88 ± 0.68	<LOD	0.853 ± 0.056	<LOD	2.83 ± 0.14	79%
Sample 1, NMIJ CRM 7405-a Hijiki	34.38 ± 0.99	Water:methanol, UAE	9.12 ± 0.23	<LOD	<LOD	<LOD	6.59 ± 0.32	28%
Sample 1, NMIJ CRM 7405-a Hijiki	34.38 ± 0.99	Water, MAE	16.52 ± 0.34	<LOD	<LOD	<LOD	7.39 ± 0.36	55%
Sample 1, NMIJ CRM 7405-a Hijiki	34.38 ± 0.99	Water:methanol, MAE	26.76 ± 0.70	<LOD	<LOD	<LOD	7.37 ± 0.35	72%
Sample 2, Hijiki cooked/dried, milled	72.6 ± 2.7	Water, UAE	66.0 ± 1.5	<LOD	0.952 ± 0.063	<LOD	5.64 ± 0.27	90%
Sample 2, Hijiki cooked/dried, milled	72.6 ± 2.7	Water:methanol, UAE	36.54 ± 0.73	<LOD	1.468 ± 0.097	0.766 ± 0.040	5.94 ± 0.29	78%
Sample 2, Hijiki cooked/dried, milled	72.6 ± 2.7	Water, MAE	48.94 ± 0.087	<LOD	1.147 ± 0.075	<LOD	5.48 ± 0.26	86%
Sample 2, Hijiki cooked/dried, milled	72.6 ± 2.7	Water:methanol, MAE	57.99 ± 0.93	<LOD	1.168 ± 0.077	<LOD	5.95 ± 0.29	88%
Sample 2a, Hijiki cooked/dried, mortar-ground	not separately reported	Water, UAE	59.6 ± 1.2	<LOD	2.63 ± 0.17	0.669 ± 0.035	4.87 ± 0.23	86%
Sample 2a, Hijiki cooked/dried, mortar-ground	not separately reported	Water:methanol, UAE	11.29 ± 0.16	<LOD	1.233 ± 0.081	<LOD	4.81 ± 0.23	46%
Sample 2a, Hijiki cooked/dried, mortar-ground	not separately reported	Water, MAE	60.7 ± 2.0	<LOD	1.195 ± 0.079	<LOD	4.12 ± 0.20	91%
Sample 2a, Hijiki cooked/dried, mortar-ground	not separately reported	Water:methanol, MAE	55.1 ± 1.5	<LOD	1.248 ± 0.082	0.596 ± 0.031	4.71 ± 0.23	88%
Sample 3, Nori sheets for sushi	19.28 ± 0.45	Water, UAE	11.85 ± 0.43	<LOD	7.88 ± 0.52	<LOD	<LOD	34%
Sample 3, Nori sheets for sushi	19.28 ± 0.45	Water:methanol, UAE	16.51 ± 0.77	<LOD	<LOD	<LOD	<LOD	100%
Sample 3, Nori sheets for sushi	19.28 ± 0.45	Water, MAE	13.83 ± 0.65	<LOD	8.97 ± 0.59	<LOD	<LOD	35%
Sample 3, Nori sheets for sushi	19.28 ± 0.45	Water:methanol, MAE	14.96 ± 0.70	<LOD	<LOD	<LOD	<LOD	100%
Sample 4, Serrated Wrack	19.37 ± 0.51	Water, UAE	2.82 ± 0.12	<LOD	1.292 ± 0.085	<LOD	<LOD	54%
Sample 4, Serrated Wrack	19.37 ± 0.51	Water:methanol, UAE	10.37 ± 0.30	<LOD	1.291 ± 0.085	<LOD	<LOD	88%
Sample 4, Serrated Wrack	19.37 ± 0.51	Water, MAE	5.35 ± 0.16	<LOD	1.098 ± 0.072	<LOD	<LOD	79%
Sample 4, Serrated Wrack	19.37 ± 0.51	Water:methanol, MAE	11.40 ± 0.35	<LOD	1.252 ± 0.082	<LOD	<LOD	89%
Sample 5, NIST SRM 3232 Kelp Powder	45.4 ± 1.4	Water, UAE	4.649 ± 0.069	<LOD	<LOD	<LOD	<LOD	100%
Sample 5, NIST SRM 3232 Kelp Powder	45.4 ± 1.4	Water:methanol, UAE	14.59 ± 0.59	<LOD	0.911 ± 0.060	<LOD	<LOD	94%

The abstract summarizes edible algae total arsenic (tAs) as (19.28 ± 0.45) mg kg-1 to (72.6 ± 2.7) mg kg-1, As(III) as <LOD to (8.97 ± 0.59) mg kg-1, As(V) as <LOD to (5.95 ± 0.29) mg kg-1, DMA as <LOD to (0.766 ± 0.040) mg kg-1, and unknown arsenic species as 28% to 100% of extracted tAs.

Reference-material checks and method figures:

NMIJ CRM 7405-a Hijiki tAs was (34.38 ± 0.99) mg kg-1 versus certified (35.8 ± 0.9) mg kg-1.
NIST SRM 3232 Kelp Powder tAs was (45.4 ± 1.4) mg kg-1 versus certified (38.3 ± 1.34) mg kg-1; the source states this was not in as good accordance as the NMIJ CRM.
The source reports LODs of 0.041 mg kg-1 for tAs, 0.12 mg kg-1 for extracted tAs, 0.55 mg kg-1 for AsB, 0.61 mg kg-1 for As(III), 0.57 mg kg-1 for DMA, 0.64 mg kg-1 for MMA, and 0.55 mg kg-1 for As(V).
MMA was not detected in any sample. AsB was detected only in one Fucus serratus extract.

UPLC-HRMS identification context from Table 4 includes DMA(V), arsenate(V), MMMTA(V), MTA(V), DMAE, DMDTA(V), MMDTA(V), DMAA, pentylarsonic acid, dimethylarsinoylribose, multiple methylated arsenosugars, and one unknown arsenic compound. The authors report a high variety of As-sugars (12 compounds) and eight additional simple organic arsenic compounds; these organoarsenic identifications are not collapsed into inorganic arsenic.

Methods (brief)

The study analyzed five seaweed materials: NMIJ CRM 7405-a Hijiki, a cooked/dried Sargassum fusiforme hijiki product, Pyropia yezoensis nori sheets for sushi, Fucus serratus serrated wrack, and NIST SRM 3232 Kelp Powder. Nori and hijiki were ground before digestion/extraction; NMIJ CRM, NIST SRM, and serrated wrack were not further ground. Total arsenic used microwave-assisted digestion with nitric acid and hydrogen peroxide at 200 °C, followed by ICP-DRC-MS monitoring 91AsO+ with 73Ge+ internal standard.

Speciation used ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) with water or water:methanol (1:1, v/v) after nitric-acid extraction was discarded because it changed arsenic (As) speciation. For each extraction, 200 mg algae material was extracted with 20 mL extracting agent for 30 min; MAE was at 60 °C and UAE at room temperature. HPLC/ICP-DRC-MS used a Hamilton PRP-X100 anion-exchange column. UPLC/ESI-MS/MS was used for unknown arsenic-species identification.

Implications

This source provides a method-centered but routeable arsenic-speciation dataset for algae/seaweed products. It supports seaweed/kelp food and algae/seaweed supplement context with total arsenic and source-measured As(III), As(V), DMA, and unknown-organoarsenic fractions. Because the source’s conclusion emphasizes arsenosugars and other unknown organoarsenic species, downstream extraction must preserve speciation and must not treat total arsenic or arsenosugars as inorganic arsenic.

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git.

Commit	Date	Change	Description
b01ec52c31	2026-08-04	major	1 section added
3171d069e3	2026-08-02	major	1 section added
90a2f9a38e	2026-07-30	major	1 section added and 1 removed; narrative text revised
eaa8eeeedf	2026-07-27	major	1 section added
50de6ab217	2026-07-27	minor	Narrative text revised

Cite this page. Prose CC BY 4.0. Structured data EU database rights reserved (licensing).

Download evidence packet

Institute of Contaminant Standards. (2026). Arsenic species and their transformation pathways in marine plants. Usefulness of advanced hyphenated techniques HPLC/ICP-MS and UPLC/ESI-MS/MS in arsenic species analysis. Heavy Metal Index. https://heavymetalindex.com/sources/lorenc2020-marine-algae-arsenic-species

The evidence packet is a JSON manifest with page checksums, contributing sources, and available data downloads. It states whether the page has a verified Git revision and provides a verification command when available. See methodology and errata for how the underlying evidence is selected and corrected.