Wehmeier et al. 2023 — Inorganic arsenic in 30 Austrian market rice products by HPLC-ICP-MS and Cola field method
Wehmeier et al. measured total arsenic (tAs) by ICP-MS and inorganic arsenic (iAs) by HPLC-ICP-MS in 30 rice and rice products purchased in Austria, as part of a method development study comparing a novel Cola-extraction field-deployable screening method against the reference HPLC-ICP-MS technique. This paper provides directly relevant food occurrence data for Austrian market rice. All As values are speciated: iAs was measured by HPLC-ICP-MS (Hamilton PRP-X100 anion exchange column, 40-mM ammonium carbonate mobile phase, Agilent 7700 ICP-MS). Total arsenic was measured by full acid digest + ICP-MS (Agilent 7900). CRM NIST 1568b recovery: tAs 299 ± 5 µg/kg (certified 285 ± 14); iAs 93 ± 1 µg/kg (certified 92 ± 10 µg/kg).
The iAs dataset across the 30 Austrian rice samples shows: range 60–249 µg/kg; mean 74% of total arsenic was iAs; DMA averaged 26% of total arsenic. Only one sample (an unpolished rice, R27) exceeded the applicable EU MCL for that rice type (250 µg/kg for unpolished/husked rice). If the infant rice MCL of 100 µg/kg were applied to all 30 samples, 22/30 would fail.
Key numbers
All concentrations in µg/kg (ppb) dry weight; measured by HPLC-ICP-MS (reference method) and ICP-MS (tAs). Full sample table in Table 2 of source.
| Statistic | tAs (µg/kg) | iAs (µg/kg) | iAs/tAs (%) |
|---|---|---|---|
| Range | 89–464 | 60–249 | 16–92% |
| Mean | 184 | ~136 (calculated) | 74% |
| Median | 165 | — | — |
| RSD (reference method precision) | 6.1% | 3.9% | — |
Selected individual sample data (Table 2):
- Highest tAs: R2, 464 µg/kg (iAs 70 µg/kg, 16% — low iAs fraction despite high tAs)
- Highest iAs: R27, 249 ± 22 µg/kg iAs (tAs 262 µg/kg, 84% iAs — exceeded EU MCL for unpolished rice at 250 µg/kg)
- Lowest tAs: R15, 89 µg/kg (iAs 60 µg/kg, 79%)
- Infant rice products were among those with iAs >100 µg/kg (EU MCL for infant rice)
EU MCLs (2023 update): infant rice 100 µg iAs/kg, polished/parboiled rice 150 µg/kg, unpolished/husked rice 250 µg/kg, rice crackers 300 µg/kg.
Field method LOD: 39 µg iAs/kg (Cola extraction). Reference method LOD: iAs 8 µg/kg, DMA 9 µg/kg, MMA 0.4 µg/kg, tAs 41 µg/kg.
Methods (brief)
iAs speciation: HPLC-ICP-MS (Agilent HPLC 1260 Infinity + Agilent 7700 ICP-MS); Hamilton PRP-X100 anion exchange column; 40-mM ammonium carbonate mobile phase pH 9.2; 1% HNO3/1% H2O2 extraction at 99 °C for 1 h. EE 97%, chromatographic recovery 95%. tAs: full acid digest (sub-boiled HNO3, UltraClave) + ICP-MS (Agilent 7900, collision cell, He gas, m/z 75). Internal standards: Ge (m/z 74), In (m/z 115). CRM NIST 1568b recovery: tAs 105%, iAs within certified uncertainty.
Implications
Certification: Austrian market rice products (n=30): iAs range 60–249 µg/kg. Only 1/30 exceeded the applicable EU MCL; 22/30 would fail the strict 100 µg/kg infant rice MCL. This dataset confirms Austrian compliance with standard rice limits but highlights that most market rice is not safe for exclusive use as infant staple.
Courses: Illustrates the non-substitutability of iAs and tAs in compliance assessments: total arsenic (range 89–464 µg/kg) did not correlate well with iAs content (some high-tAs samples had only 16% iAs fraction). HPLC speciation is non-negotiable for regulatory and health assessment purposes.
App: Austrian market rice (n=30): iAs 60–249 µg/kg; mean iAs 74% of tAs. Infant rice products require the strictest standard (100 µg/kg iAs); most polished market rice falls in the 60–176 µg/kg range by HPLC-ICP-MS.