Costa 2018 - Arsenic speciation method validation in rice flour

Costa’s doctoral thesis developed an in-situ quaternary-ammonium-salt solid-phase extraction method coupled to flow-injection hydride-generation atomic absorption spectrometry for arsenic speciation in rice matrices. The routeable matrix is rice flour certified reference material, not salt. The method validation measured IRMM-804 Rice Flour at 0.045 +/- 0.007 mg/kg total As versus a certified 0.049 +/- 0.004 mg/kg, with As(III) measured at 0.043 +/- 0.004 mg/kg and DMA not detected.

Key numbers

• Certified reference material: IRMM-804 Rice Flour.
• Certified total As concentration: 0.049 +/- 0.004 mg/kg.
• Proposed method result for IRMM-804:
  • As(III): 0.043 +/- 0.004 mg/kg.
  • DMA: not detected.
  • Total As: 0.045 +/- 0.007 mg/kg.
• Method accuracy for total As: 92.33% versus the certified value.
• Preconcentration factor for As(III): 16.76.
• Detection and quantification limits:
  • As(III): LOD 0.04 ug/L and 0.01 ug/g; LOQ 0.12 ug/L and 0.04 ug/g.
  • DMA: LOD 0.46 ug/L and 0.15 ug/g; LOQ 1.55 ug/L and 0.51 ug/g.
• Precision: coefficient of variation 5.49% for a 10.0 ug/L As(III) solution.
• Analytical frequency: 30 samples per hour.

Methods (brief)

The thesis validates in-situ solid-phase extraction using tetra-n-butylammonium perchlorate and APDC complexation, followed by FI-HG AAS detection. Rice flour was solubilized by alkaline decomposition with Universol, and total As determination required pre-reduction of pentavalent arsenic before hydride generation. The method selectively extracts As(III) under the optimized conditions and uses a difference/pre-reduction workflow for total inorganic/total As handling. The source does not report a consumer-market survey of rice samples; it reports a certified-reference-material validation result.

Implications

• Testing: useful method-validation evidence for rice-flour arsenic speciation by FI-HG AAS.
• Rice: the only extractable food-matrix value is the IRMM-804 Rice Flour CRM result; treat as analytical validation, not a market occurrence distribution.
• Standards workbench: do not include as a retail rice or salt occurrence row.
• Speciation: the thesis distinguishes As(III), DMA, and total As. Do not substitute total As for inorganic arsenic in downstream routing.

Wiki pages this source may touch

• rice-flour
• rice
• cereal-products
• arsenic-total
• arsenic-inorganic

Verification notes

• The source title and text are in Portuguese; metadata comes from the PDF catalog page and DOI line.
• The auto-fetched filename/wishlist target was salt iAs, but the PDF is a rice-flour analytical-method thesis. No salt matrix is measured.
• Because the source uses a certified reference material rather than sampled commercial rice, it should route mainly as testing/method evidence.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.