Overview - ISO 17239:2004 (Arsenic in fruits & vegetables)
ISO 17239:2004 specifies a standardized laboratory method for the determination of arsenic content in fruits, vegetables and derived products using hydride generation atomic absorption spectrometry (hydride generation AAS). The method defines sample preparation (closed-vessel nitric acid digestion), chemical reduction and hydride generation, instrumental measurement (AAS at 193.7 nm with background correction), calculation and reporting requirements. It is based on established AOAC procedures and was prepared by ISO/TC 34 (Food products).
Key topics and technical requirements
- Scope and principle: Decomposition of organic matter by closed-system HNO3 digestion; reduction of As(V) to As(III) with potassium iodide; generation of arsine (AsH3) via sodium borohydride and atomization by a flame-heated quartz cell for AAS measurement.
- Reagents & solutions: Requires analytical-grade reagents (concentrated HNO3, HCl solutions, Mg salts, 4% NaBH4 in 4% NaOH, fresh KI solution, arsenic standard solutions).
- Apparatus: Hydride generator assembly, PTFE-coated grinder, 70 ml PTFE/PTFE-lined decomposition vessel, AAS instrument (air/acetylene burner or hydrogen-nitrogen-entrained air flame) with deuterium-arc background correction; oven and furnace for digestion/oxidation.
- Sample preparation: Representative sampling, homogenization (PTFE-coated grinder), thawing protocol for frozen products, test portion typically 0.30 g (dry basis) for closed-vessel digestion (document cautions not to exceed vessel specifications).
- Calibration & measurement: Multi-point calibration using arsenic standards (example series 0–0.25 µg arsenic per aliquot), reproducible inversion/mixing of generator flask to produce sharp absorbance peaks, read against calibration curve.
- Calculation & quality criteria: Arsenic concentration expressed in mg/kg, blank correction, and documented precision characteristics (repeatability r and reproducibility R are defined; interlaboratory results summarized in Annex B).
- Reporting: Requires sample identification, sampling method, method reference, instrument/operating details, deviations/incidents and final results.
Practical applications
- Food safety testing: Regulatory compliance checks for arsenic in fresh and processed fruit and vegetable products.
- Quality control: Routine monitoring by food manufacturers and ingredient suppliers.
- Analytical laboratories: Method validation, accreditation and routine determination in contract testing and research labs.
- Public health and research: Dietary exposure assessments and surveillance studies for arsenic in food matrices.
Who should use this standard
- Accredited food testing laboratories, manufacturers’ QC labs, regulatory agencies, and researchers performing arsenic analyses in fruits, vegetables and derived foods seeking a validated hydride generation AAS procedure.
Related standards
- ISO 17239:2004 references AOAC Official Methods as the basis for the procedure. It was developed by ISO/TC 34 (Food products), Subcommittee SC 3 (Fruit and vegetable products). For laboratory accreditation, consult ISO/IEC 17025 and relevant national food safety regulations.