ISO 15597:2001

Overview - ISO 15597:2001 (WDXRF for chlorine & bromine in petroleum)

ISO 15597:2001 specifies a quantitative laboratory method to determine chlorine and bromine content in liquid petroleum products, synthetic oils, fluids and additives (including used oils) using wavelength-dispersive X‑ray fluorescence (WDXRF) spectrometry. The method applies to samples soluble in organic solvents of negligible or known halogen content and covers mass-fraction ranges of chlorine 0.0005%–0.1000% (m/m) and bromine 0.0010%–0.1000% (m/m). The standard details sample preparation, calibration, instrument settings, and calculation of results.

Key topics and technical requirements

• Principle: Measure net fluorescence count rates for Cl-Kα and Br-Kα lines and use a bismuth internal standard (Bi Mα or Lα) to compute count‑rate ratios and determine concentration from calibration curves.
• Detection ranges: Chlorine down to 0.0005% (m/m); bromine down to 0.0010% (m/m). Note: used lubricants may reduce sensitivity (practical lower limit ~0.0050% m/m).
• Apparatus & optics: A WDXRF spectrometer with suitable anode (e.g., Rh, Sc, Cr), appropriate analysing crystals (Ge for Cl, LiF for Br), helium optical path, and proportional or scintillation detectors with pulse‑height analysis.
• Sample prep: Dissolve sample in high‑purity white oil, mix with a prepared 1% triphenylbismuth solution (with 5% 2‑ethylhexanoic acid) as internal standard, homogenize, and measure in chlorine/bromine‑free sample cells.
• Calibration: Use certified reference materials or primary standards (e.g., 1‑chlorooctane, 1,1,2,2‑tetrabromoethane) to prepare stock and standard solutions at specified concentrations (0.0005% to 0.05% listed). Construct and routinely check calibration curves; polynomial fits may be required.
• Interferences & limitations: Most elements do not interfere; lead can interfere at contents above 0.1500% (m/m). Care is required for used oils with multiple potential interfering elements.
• Safety & quality: Warns of hazardous chemicals (e.g., tetrabromoethane) and emphasizes good laboratory practice, clean glassware and control of halogen‑containing vapors.

Applications and users

• Routine quality control and compliance testing in petroleum refineries, lubricant manufacturers, additive suppliers and third‑party testing laboratories.
• Environmental and regulatory labs monitoring halogenated contaminants in fuels, oils and waste oils.
• R&D groups developing additive packages or degradation studies where precise halogen quantification is required.

Related standards

• ISO 3170:1988 - Petroleum liquids - Manual sampling
• ISO 3171:1988 - Petroleum liquids - Automatic pipeline sampling
• ISO 4259:1992 - Precision data and application to test methods

Keywords: ISO 15597:2001, WDXRF, wavelength-dispersive X‑ray fluorescence, chlorine determination, bromine determination, petroleum products, used oils, bismuth internal standard, calibration, halogen analysis.