ISO 10304-3:1997 - Overview
ISO 10304-3:1997 is an International Standard for water quality analysis that specifies ion chromatography methods for the determination of selected dissolved anions in aqueous solutions. Part 3 covers the determination of chromate, iodide, sulfite, thiocyanate and thiosulfate using liquid (ion) chromatography with appropriate sample pretreatment, eluents and detectors. The standard defines working ranges, detector options, calibration practices and quality checks needed for routine laboratory use.
Key topics and technical requirements
- Analytes covered: chromate (CrO4 2–), iodide (I–), sulfite (SO3 2–), thiocyanate (SCN–), thiosulfate (S2O3 2–).
- Detection methods: conductivity detector (CD) - often used with suppressors; UV detectors (direct or indirect); amperometric detectors (AD). Working detector voltages and wavelengths are specified qualitatively (e.g., UV λ ranges and AD oxidation potentials depend on eluent pH).
- Working ranges (examples from Table 1):
- Chromate: 0.05–50 mg/L (UV λ = 365 nm)
- Iodide: 0.1–50 mg/L (CD or UV λ = 205–236 nm; AD ≈ 0.7–1.1 V)
- Sulfite: 0.1–50 mg/L (CD) and 0.5–50 mg/L (UV λ = 205–220 nm)
- Thiocyanate, Thiosulfate: 0.1–50 mg/L (CD/UV/AD options)
- Chromatographic performance: minimum column peak resolution requirement R ≥ 1.3 for targeted ions.
- Eluents and reagents: examples include sodium carbonate/sodium hydrogen carbonate eluents (with optional 4‑hydroxybenzonitrile to improve elution/tailing), and phthalic acid–based eluents for non‑suppressed systems. Eluent degassing and short storage (renew every 2–3 days) are recommended.
- Calibration & quality assurance: calibration and linear working-range determination per ISO 8466-1; validation checks and replicate determinations when required.
- Sample handling: recommends appropriate pretreatment (e.g., dilution) and references ISO 5667 series for sampling, preservation and handling.
Practical applications and users
ISO 10304-3 is intended for analytical laboratories performing environmental and water‑quality monitoring, including:
- Municipal and industrial water testing labs
- Environmental monitoring agencies assessing surface, ground or process waters
- Laboratories validating anion concentrations in drinking water, wastewater streams and industrial effluents (in conjunction with other ISO 10304 parts)
- Instrument vendors and method developers implementing ion‑chromatography methods and QA procedures
The standard helps users select detectors, eluents and operating ranges, and ensures comparability and traceability of dissolved-anion measurements.
Related standards
- ISO 10304-1, -2, -4 (other parts of the same series)
- ISO 5667-1/-2/-3 (sampling guidance, preservation and handling)
- ISO 8466-1 (calibration and evaluation of analytical methods)
Keywords: ISO 10304-3, water quality, ion chromatography, dissolved anions, chromate, iodide, sulfite, thiocyanate, thiosulfate, conductivity detector, UV detector, amperometric detector, eluents, sample pretreatment.
Open preview (PDF)Water quality — Determination of dissolved anions by liquid chromatography of ions — Part 3: Determination of chromate, iodide, sulfite, thiocyanate and thiosulfate