ISO 5961:1994 PDF

Overview

ISO 5961:1994 - "Water quality - Determination of cadmium by atomic absorption spectrometry" defines two validated procedures for measuring cadmium (Cd) in water and wastewater using atomic absorption spectrometry (AAS). The standard covers:

• Flame AAS (air–acetylene): aspiration of acidified samples and measurement at 228.8 nm (typical range given 0.05 mg/L to 1 mg/L; extendable by dilution or evaporation).
• Electrothermal (graphite furnace) AAS: injection of acidified samples into an electrically heated graphite tube and measurement at 228.8 nm (suitable for much lower concentrations - example dosing volume 10 µL giving a typical range ~0.3 µg/L to 3 µg/L).

ISO 5961:1994 is intended for routine water quality testing, with guidance on reagents, sample preparation, calibration, blank tests and quality controls.

Key Topics and Requirements

• Analytical principles: flame AAS vs electrothermal atomization AAS, both at 228.8 nm.
• Sensitivity & ranges: flame method for mg/L levels; electrothermal for µg/L (trace) levels.
• Sample handling: collection in clean polyethylene or borosilicate containers, acid-cleaning of glassware, filtration (0.45 µm) for dissolved Cd, and acidification with nitric acid to pH