4.1 This test method is suitable for determining trace concentrations of iron in a wide variety of products, provided that appropriate sample preparation has rendered the iron and sample matrix soluble in water or other suitable solvent. Each sample matrix must be investigated for suitability using this test method.

4.2 This test method assumes that the amount of color developed is proportional to the amount of iron in the test solution. The calibration curve is linear over the specified range.

1.1 This test method covers the determination of iron in aromatic hydrocarbons, their derivatives, and related chemicals in the range from 0.01 to 0.2 μg/g using [3-(2-pyridyl)-5,6-bis(4-phenylsulfonic acid)-1,2,4-triazine, monosodium salt, monohydrate] (PDTS)2 reagent solution. The range may be extended through the use of a 5- or 10-cm cell or by suitable dilution of the sample solution.

1.2 The limit of detection (LOD) is 0.01 µg/kg for iron and the limit of quantitation (LOQ) is 0.04 µg/kg.

Note 1: The LOD and LOQ were calculated using data from the ILS.

1.3 This test method is intended to be general for the final steps in the determination of iron and does not include procedures for sample preparation.

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.5 Review the current Safety Data Sheets (SDS) for detailed information concerning toxicity, first-aid procedures, and safety precautions.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see Section 8.

1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.