GB/T 4348.3-2012 in English

《GB/T 4348.3-2012工业用氢氧化钠 铁含量的测定　1，10-菲啰啉分光光度法》由TC63（全国化学标准化技术委员会）归口，TC63SC6（全国化学标准化技术委员会氯碱分会）执行，主管部门为中国石油和化学工业联合会。

Foreword

This standard is developed in accordance with the rules given in GB/T 1.1-2009.

This standard replaces GB/T 4348.3-2002 Sodium hydroxide for industrial use - Determination of iron content – 1, 10-phenanthroline photometric method, and the following main technical changes have been made with respect to GB/T 4348.3-2002 (previous edition):

——The normative references are modified (see clause 2, clause 2 of Edition 2002);

——The reducing agent reducing Fe3+ to Fe2+ is modified (see 3, 6.1.1 and 6.4; 3, 6.1.1 and 6.3.3 of Edition 2002);

——The reagents are partially modified (see clause 4; clause 4 of Edition 2002);

——The preparation of standard colorimetric solution is modified (see 6.1.1; 6.1.1 of Edition 2002);

——The solution for adjusting the zero point of the spectrophotometer is modified (see 6.1.2 and 6.5; 6.1.2 and 6.3.4 of Edition 2002);

——The sampling volume is modified (see 6.2; 6.2 in Edition 2002);

——The result calculation formula is modified (see clause 7; clause 7 of Edition 2002);

——The clause of test report is added (see clause 9);

This standard was proposed by the China Petroleum and Chemical Industry Association.

This standard is under the jurisdiction of SAC/TC 63/SC 6 Subcommittee on Chlor Alkali of National Technical Committee on Chemical of Standardization Administration of China.

The previous editions replaced by this standard are as follows:

——GB/T 4348.3-1984 and GB/T 4348.3-2002.

Foreword i
1 Scope
2 Normative references
3 Principle
4 Reagents and materials
5 Apparatus
6 Analytical procedures
7 Result calculation
8 Allowable deviation
9 Test report