GB/T 11140-2008 in English

《GB/T 11140-2008石油产品硫含量的测定 波长色散X射线荧光光谱法》由TC280（全国石油产品和润滑剂标准化技术委员会）归口，TC280SC1（全国石油产品和润滑剂标准化技术委员会石油燃料和润滑剂分会）执行，主管部门为国家标准化管理委员会。
本标准根据ＡＳＴＭ Ｄ２６２２：２００７重新起草。本标准代替ＧＢ／Ｔ１１１４０―１９８９《石油产品硫含量测定法（Ｘ 射线光谱法）》，ＧＢ／Ｔ１１１４０―１９８９是参照采用ＡＳＴＭ Ｄ２６２２：１９８２制定的。本标准与ＧＢ／Ｔ１１１４０―１９８９相比主要技术差异如下：
―――本标准的名称进行了修改，由《石油产品硫含量测定法（Ｘ 射线光谱法）》修改为《石油产品硫含量的测定　波长色散Ｘ 射线荧光光谱法》；
―――本标准扩充了适用范围；
―――本标准的测定限值有所改变，由１０ｍｇ／ｋｇ～５．０％（质量分数）改为３ｍｇ／ｋｇ～４．６％（质量分数）；
―――本标准引用标准有所增加；
―――本标准干扰元素有增减；
―――本标准的试验步骤章中不同晶体的２θ 角度有增减；
―――本标准增加了意义与用途、干扰因素、质量控制三个章；
―――本标准将ＧＢ／Ｔ１１１４０―１９８９方法中的取样、准备工作章修改为取样和试样制备、校准章；
―――本标准的精密度进行了修改；
―――本标准增加了附录Ａ《精密度的说明》。

1 Scope

1.1 This standard covers the determination of total sulfur in petroleum and petroleum products that are single-phase and either liquid at ambient conditions, liquefiable with moderate heat, or soluble in hydrocarbon solvents. This standard is applicable to the determination of diesel fuel, jet fuel, kerosene, other distillate oil, naphtha, residual oil, lubricating base oil, hydraulic oil, crude oil, unleaded gasoline, gasohol and biodiesel.

1.2 The combined range of limit of quantitation in this standard calculated by statistical procedures in ASTM D6259 is 3mg/kg.

1.2.1 The values of the limit of quantitation (LOQ) and method precision for a specific laboratory’s instrument depends on instrument source power (low or high power), sample type, and the practices established by the laboratory to perform the method.

1.3 Samples containing more than 4.6% (mass fraction) sulfur may be diluted to bring the sulfur concentration of the diluted material within the scope of this standard. Samples that are diluted may have higher errors than non-diluted samples indicated in Clause 14.

1.4 Volatile samples (such as high vapor pressure gasolines or light hydrocarbons) may not meet the stated precision because of selective loss of light materials during the analysis.

1.5 A fundamental assumption in this standard is that the standard and sample matrices are well matched, or that the matrix differences are accounted for (see 12.2). Matrix mismatch will be caused by C/H ratio differences between samples and standards or by the presence of other interfering heteroatoms or species (see Table 1).

1.6 The values stated in SI units are to be regarded as the standard.

1.7 This standard only explains some special dangers related to the test process, and does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2 Normative references

The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections) to, 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 4756 Petroleum liquids - Manual sampling (GB/T 4756-1998, eqv ISO 3170: 1988)
GB/T 8170 Rules for rounding off of numerical values
GB/T 17040 Standard test method for sulfur in petroleum and petroleum products by energy dispersive X-ray fluorescence spectrometry
SH/T 0631 Determination of barium, calcium, phosphorus, sulfur and zinc in lubricating oils and additives (X-ray fluorescence spectrometry)
ASTM D6259 Standard practice for determination of a pooled limit of quantitation
ASTM D6299 Practice for applying statistical quality assurance and control charting techniques to evaluate analytical measurement system performance
ASTM D7343 Practice for optimization, sample handling, calibration, and validation of X-ray fluorescence spectrometry methods for elemental analysis of petroleum products and lubricants

3 Summary of test method

The sample is placed in the X-ray beam, and the intensity of the sulfur Kα line at 0.5373nm is measured. The background intensity, measured at a recommended wavelength of 0.5190nm (0.5437nm for a Rh target X-ray tube) is subtracted from the peak intensity. The resultant net counting rate is then compared to a previously prepared calibration curve to obtain the concentration of sulfur in mg/kg or mass % (see Clause 12).

Foreword i
1 Scope
2 Normative references
3 Summary of test method
4 Significance and use
5 Interferences
6 Apparatus
7 Reagents and materials
8 Sampling and sample preparation
9 Calibration
10 Procedure
11 Calculation
12 Reporting
13 Quality control
14 Precision and Bias
15 Keywords
Annex A (Informative) Additional precision statements