Downloaded from orbit.dtu.dk on: Apr 20, 2019
Inorganic arsenic - SPE HG-AAS method for RICE tested in-house and collaboratively
Rasmussen, Rie Romme; Qian, Yiting; Sloth, Jens Jørgen
Publication date: 2013 Document Version Early version, also known as pre-print Link back to DTU Orbit
Citation (APA): Rasmussen, R. R., Qian, Y., & Sloth, J. J. (2013). Inorganic arsenic - SPE HG-AAS method for RICE tested inhouse and collaboratively. Poster session presented at 6th International Symposium on Recent Advances in Food Analysis, Prague, Czech Republic.
General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. Users may download and print one copy of any publication from the public portal for the purpose of private study or research. You may not further distribute the material or use it for any profit-making activity or commercial gain You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Rasmussen RR Qian Y Sloth JJ [email protected]
SPE HG-AAS RICE METHOD TESTED IN-HOUSE AND COLLABORATIVELY Extraction 0.5 g (dry weight) sample extracted for 60 minutes at 90 °C with 10 ml of a dilute acidic mixture (0.1 M HNO3 and 3% H2O2)
Water bath extraction
method(s) are needed for establish-
ment of a maximum level (ML) for
Detection Pre-reduction; AsV AsIII by mixing eluate with KI, HCl and ascorbic acid Hydride generation; HCl, NaOH and NaBH4 Instrument settings; heated cell (900° C), As lamp (193.7 nm wave length, 0.5 nm slit width)
inorganic arsenic (iAs) in rice as recently emphasised by the European
Food Safety Authority (2009), the World Health Organization (2011) and Codex Alimentarius (2012).
The charge of the arsenic species depends on pH pH 5-7
Rice contains most often three forms of the trace element arsenic; iAs and the
3. Load buffered sample: pH 5.0-7.5
of less toxicological importance.
As H H
SPE HG-AAS vs HPLC-ICP-MS A comparison of the results from the
5. Elute SPE, 0.4 M HNO3
two methods (Fig. 3) showed good agreement. SPE fractions
0.9 0.8 HPLC-ICP-MS (mg kg-1)
Load Wash Eluate
Inorganic arsenic (V)
This SPE HG-AAS method enables selective determination of inorganic arsenic in rice and rice products by use of inexpensive instrumentation (HGAAS) and is a candidate method for future control.
0.7 0.6 0.5 0.4 Day 1
Day 3 Day 4
Figure 1. Overlaid HPLC-ICP-MS chromatogram of 3 SPE fractions (load, wash and eluate) of a rice sample (NIST1568a) containing both inorganic and organoarsenic species.
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 SPE HG-AAS (mg kg-1)
Figure 3. Determination of inorganic arsenic by two different methods; HPLC-ICP-MS and SPE HG-AAS. In total results for 84 spiked and natural incurred rice samples analysed on four different days. The correlation is y=x (99% confidence interval regression analysis by Excel 2010).
VALIDATION RESULTS In-house validation was satisfying
Table 1. In-house validation Spiked rice samples
Rice reference materials
Repeatability RSDir (%)
Reproducibility RSDIR (%)
(Tab 1.) and was in accordance with Target level (mg·kg-1)
previous results for marine samples (Rasmussen et. al 2013). The LOD (0.02
4. Wash SPE, 0.5 M CH3COOH
intensity 75As (cps)
DMA and MA are generally considered
(DMAV). Dietary intake of iAs is of carcinogenicity to humans, whereas
SPE strong anion exchange
2. Equilibrate SPE, 35 mM (NH4)2CO3, 0.05 M HNO3, 1.5% H2O2
acid (MAV) and dimethylarsinic acid to
is negatively charged
1. Pre-condition of SPE, MeOH
methylated species monomethylarsonic
was below the proposed
maximum levels (0.2-0.3 mg·kg-1).
Observations (N) Mean recovery (%)
*) Consensus mean values: IMEP-107 (de la Calle MB et al., 2011 TrAC 30:641– 651) and NIST1568a (Raab A et al., 2009 J Environ Monit 11:41–44). **) One outlier result discarded (0.048 mg·kg-1).
RICE SAMPLES The iAs concentration determined by SPE HG-AAS in 36 rice samples purchased on the Danish retail market varied (0.03–0.60 mg·kg-1), with the
Collaborative test of the SPE separation method on a wholemeal rice meal sample
highest concentration found in a red
gave a satisfactory HorRat value of 1.6 among 10 laboratories.
References Codex (2012) Proposed draft maximum levels for arsenic in rice (at step 3). European Food Safety Authority (2009) EFSA Journal 7(10), 1351:1-199 Rasmussen et al (2013), ABC, doi 10.1007/s00216-013-6936-8 World Health Organization (2011) WHO Technical Report Series 959
Funding was received from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 211326 www.conffidence.eu