ISO 2460:1973

Overview

ISO 2460:1973 specifies a precise photometric method for determining the iron content in sodium hydrogen carbonate used for industrial purposes. This international standard employs the 1,10-phenanthroline photometric technique, which is widely recognized for its accuracy and reliability in quantitative chemical analysis. The method is designed to measure iron contents equal to or greater than 0.1 mg/kg, making it suitable for quality control and safety assurance in industrial chemical processes.

The principle of the test involves reducing trivalent iron (Fe³⁺) to bivalent iron (Fe²⁺) using hydroxylammonium chloride, followed by the formation of an iron(II)-1,10-phenanthroline complex. The colored complex is then measured photometrically at approximately 510 nm, allowing for the precise determination of iron concentration.

Key Topics

• Scope and Application Applicable to sodium hydrogen carbonate products with iron contents ≥ 0.1 mg/kg, commonly used in various industrial settings.

• Chemical Principles

  • Reduction of Fe³⁺ to Fe²⁺ by hydroxylammonium chloride
  • Formation of an iron(II)-1,10-phenanthroline complex
  • Photometric detection at 510 nm wavelength

• Preparation and Reagents Important reagents include hydrochloric acid, ammonia solution, hydroxylammonium chloride, buffer solution (pH 4.9), bromine water, methyl orange indicator, and standard iron solutions.

• Apparatus Requirements

  • Spectrophotometer or photoelectric absorptiometer with suitable filters (500-520 nm transmission)
  • Volumetric flasks and standard laboratory glassware for sample and reagent preparation

• Procedure Steps

  • Neutralization and preparation of test solutions
  • Calibration curve development using iron standard solutions
  • Photometric measurement of absorbance at 510 nm

• Calculation and Reporting The iron content (mg/kg) is calculated based on absorbance and calibration data. The test report includes reference to the ISO method, expression of results, and notes any deviations or anomalies encountered during testing.

Applications

• Quality Control in Chemical Manufacturing Ensuring sodium hydrogen carbonate meets industrial purity standards by monitoring iron impurities.

• Industrial Safety and Compliance Verifying iron content to meet regulatory requirements and prevent contamination in chemical processes.

• Research and Development Used in labs for method validation and analysis of raw materials to optimize product quality.

• Environmental Monitoring Detecting iron impurities which may affect downstream processes or environmental discharge.

Related Standards

• ISO standards related to chemical analysis and purity assessment, such as:

  • ISO 787 series for chemical analysis of cement and related materials
  • Other ISO methods for trace metal determination in industrial chemicals

• National and international standards on photometric and spectrophotometric methods for metal ion quantification.

• Complementary ISO standards on reagent preparation, laboratory water quality, and instrument calibration to ensure accuracy and repeatability.

By adhering to the ISO 2460:1973 standard, industries can achieve precise and reproducible measurements of iron content in sodium hydrogen carbonate, contributing to enhanced product quality, process efficiency, and regulatory compliance.