Overview
ISO 8288:1986 - Water quality specifies validated flame atomic absorption spectrometric (FAAS) methods for the determination of six trace metals in water: cobalt, nickel, copper, zinc, cadmium and lead. The standard defines three procedures:
- Method A - direct determination by FAAS for relatively high concentrations and simple matrices;
- Method B - chelation with APDC and extraction into MIBK for lower concentrations / complex matrices;
- Method C - chelation with HMA–HMDC and extraction into a DIPK–xylene solvent mix for enhanced preconcentration.
ISO 8288:1986 covers sampling, sample preservation (acidification), apparatus requirements (hollow‑cathode lamps, nebulizer‑burner, appropriate flames), calibration, blanking, background correction and result calculation.
Key topics and technical requirements
- Target analytes: Co, Ni, Cu, Zn, Cd, Pb.
- Three analytical routes: direct FAAS (fast, for higher concentrations) and two solvent‑extraction preconcentration methods (APDC/MIBK and HMA–HMDC/DIPK‑xylene) for low‑level determinations and complex matrices.
- Sample handling: acidify samples (HNO3) for total metals or filter (0.45 µm) and acidify for dissolved metals; use cleaned glassware (nitric acid wash) and deionized water.
- Calibration & quality control: prepare multi‑point calibration from certified standards, run blank tests in parallel, use standard additions to check matrix effects, and maintain stable flame/aspiration conditions.
- Background correction: employ continuous background correction if available; otherwise measure and subtract non‑specific absorbance using a nearby spectral line (zirconium/deuterium/neon/argon).
- Extraction ratios & sensitivity: Methods B and C enable preconcentration (typical test‑portion:extraction solvent ratios 20:1, possibility up to 50:1) to reach lower µg/L detection capability; select method based on sample COD and matrix.
Practical applications and users
ISO 8288 is used by:
- Environmental and municipal water testing laboratories (surface water, groundwater, drinking water);
- Industrial effluent and process monitoring labs;
- Regulatory agencies and conformity assessment bodies validating compliance with metal concentration limits;
- Research laboratories performing trace metal surveys.
It guides labs in selecting the appropriate FAAS method based on concentration range, matrix complexity and required detection limits, ensuring reproducible, traceable results.
Related standards
- Standards and guidance from ISO Technical Committee ISO/TC 147 (Water quality) and other FAAS and metal‑analysis protocols complement ISO 8288. Laboratories should refer to relevant local and international water‑quality regulations when applying the methods.
Keywords: ISO 8288, water quality, flame atomic absorption spectrometry, FAAS, cobalt, nickel, copper, zinc, cadmium, lead, APDC, MIBK, HMA, HMDC, DIPK, xylene, chelation, metal analysis.
