GB/T 23993-2009 in English

《GB/T 23993-2009水性涂料中甲醛含量的测定 乙酰丙酮分光光度法》由TC5（全国涂料和颜料标准化技术委员会）归口，主管部门为中国石油和化学工业联合会。
本标准规定了水性涂料中甲醛含量的测定方法。
本标准适用于甲醛含量不小于5mg/kg的水性涂料及其原料的测试。

1 Scope

This standard specifies determination method of formaldehyde content of waterborne coatings.

This standard is applicable to testing of waterborne coatings with formaldehyde content not less than 5mg/kg and their raw materials.

2 Normative References

The following normative documents contain provisions which, through reference in this standard, constitute provisions of this standard. For dated reference, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.

GB/T 601 Chemical Reagent - Preparations of Standard Volumetric Solutions
GB/T 3186 Paints Varnishes and Raw Materials for Paints and Varnishes - Sampling (GB/T 3186-2006, ISO 15528: 2000, IDT)
GB/T 6682 Water for Analytical Laboratory Use-Specification and Test Methods(GB/T 6682-2008, ISO 3696: 1987, MOD)

3 Principle

Formaldehyde is separated from the sample through distillation. In the acetic acid-ammonium acetate buffer solution (pH=6), formaldehyde and acetylacetone in the distillate, once heated, will react and form a stable yellow complex, which is cooled and then subjected to absorbance testing at a wavelength of 412nm. Formaldehyde content of the specimen is calculated according to the standard work curve.

Foreword i
1 Scope
2 Normative References
3 Principle
4 Reagents and Materials
5 Apparatus
6 Sampling
7 Test Procedures
8 Expression of Results
9 Precision
10 Test Report