1 Scope
1.1 This standard specifies the determination of trace organic chloride in aromatic hydrocarbons for industrial use by microcoulometry.
This standard is applicable to samples with organic chlorine concentrations from 0.5 mg/kg to 25 mg/kg in aromatic hydrocarbons for industrial use.
This standard is not applicable to samples with sulfur and nitrogen concentrations greater than 0.1% (m/m). Presence of bromide, iodide and inorganic chloride in the sample will make the determination results biased high.
1.2 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 to establish appropriate safety and health practices and ensure compliance with relevant national regulatory provisions.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments to (excluding any corrigendum), or revisions of, any of these publications do not apply. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the latest editions of the standards indicated below. For any undated references, the latest edition of the document referred to applies.
GB/T 3723 Sampling of chemical products for industrial use—Safety in sampling
GB/T 6680 General rules for sampling liquid chemical products
GB/T 6682 Water for analytical laboratory use—Specification and test methods
GB/T 8170 Rules for rounding off of numerical values
3 Summary of method
A sample is injected into a combustion tube where it is mixed with oxygen and burns. Oxidative pyrolysis converts the organic chlorine in the sample to hydrogen chloride that then, by the carrier gas, is brought into a titration cell where it reacts with the silver ions present in the electrolyte (Ag++Cl-→AgCl↓). The silver ion thus consumed is coulometrically replaced by electrolysis and the total electrical work to replace it is used to calculate the organic chloride concentration in accordance with the Faraday's laws of electrolysis.
Foreword i
1 Scope
2 Normative references
3 Summary of method
4 Reagents and materials
5 Apparatus
6 Sampling
7 Preparations
8 Test procedure
9 Expression of analysis results
10 Precision
11 Report
Annex A (Informative)
