GB/T 12737-2008 in English

《GB/T 12737-2008工业用化工产品中以硫酸根表示的痕量硫化合物测定的通用方法 还原和滴定法》由TC63（全国化学标准化技术委员会）归口，TC63SC1（全国化学标准化技术委员会无机化工分会）执行，主管部门为中国石油和化学工业联合会。
本标准规定了工业用化工产品中以硫酸根表示的痕量硫化合物测定的通用方法还原和滴定法。 本标准等同采用国际标准ＩＳＯ６２２８：１９８０（Ｅ）《工业用化工产品　以硫酸根表示的痕量硫化合物测
定的通用方法　还原和滴定法》。 本标准代替ＧＢ／Ｔ１２７３７―１９９１《化工产品中痕量硫酸盐测定的通用方法　还原滴定法》。
本标准与ＧＢ／Ｔ１２７３７―１９９１相比，主要变化如下：
―――为尊重ＩＳＯ 原文，制备还原液时使用的氢碘酸的质量分数由大于５５％改为约５７％，浓盐酸改为３８％（本版４．４，１９９１年版３．６）；
―――删除了乙酸汞标准滴定溶液或硝酸汞标准滴定溶液浓度的计算公式（本版４．４，１９９１年版３．６）
―――删除了硫酸盐（以ＳＯ４ 计）含量的计算公式（本版４．４，１９９１年版３．６）；
―――调整了部分干扰离子的最大允许限量（本版附录Ｂ，１９９１年版附录Ａ）；
―――删除了甲酸、草酸样品的前处理方法（本版附录Ａ，１９９１年版附录Ｂ）；
―――删除了氢碘酸的提纯方法（１９９１年版附录Ｃ）。

Scope

This standard specifies the general method for the determination of trace sulfur compounds expressed as sulfate radicals in industrial chemical products - reduction and titration. The method for treating the sample to convert the sulfur compound to sulfate should be specified in the standard for the chemical product to which this method is applicable, with any modifications that may be required to the general procedure, if necessary. This method is suitable for determining the content of sulfate (SO₄^2-) in the solution or directly in the sample in some cases. The range is 4.5μg～450μg. The water content in the test solution taken for the determination shall not exceed 2mL. The content of interfering elements in the test sample should not exceed the allowable limit, which is stipulated in the standards of the relevant chemical products using this method. The sulfur compounds in the product should exist in the form of sulfate radicals, and appropriate pretreatment should be carried out for samples containing other sulfur compounds to obtain sulfate radical-containing test solutions. The expected precision of this method is ±5%.