1 Scope
1.1 This standard specifies the determination of purity and hydrocarbon impurities of petroleum p-xylene by gas chromatography and external calibration.
1.2 It is applicable to determining of p-xylene with purity not less than 99% (mass fraction) and hydrocarbon impurities such as C1~C10 non-aromatic hydrocarbons, benzene, toluene, ethylbenzene, dimethylbenzene and C9~C10 aromatic hydrocarbons at individual concentrations (mass fraction) ranging from 0.001%~1.000%.
1.3 This standard does not purport to address the safety problems associated with its use. It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory provisions.
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. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For undated references, the latest edition applies.
GB/T 3723 Sampling of chemical products for industrial use - Safety in sampling (GB/T 3723-1999, ISO 3165: 1976, idt)
GB/T 6680 General rules for sampling liquid chemical products
GB/T 8170 Rules for rounding off of numerical values
3 Method summary
Under the conditions specified in this standard, a proper amount of specimen is injected into a chromatograph equipped with a flame ionization detector (FID). p-xylene and various impurity components are effectively separated on chromatographic column, the areas of all peaks except that assigned as p-xylene are measured, and the content of each impurity is calculated by external calibration. The purity of p-xylene is calculated by subtracting the total amount of impurities from 100.00.
Foreword i
1 Scope
2 Normative References
3 Method summary
4 Reagents and materials
5 Apparatus
6 Sampling
7 Determination procedures
8 Calculation of results
9 Expression of analytical results
10 Repeatability limit
11 Report
Annex A (Informative) Comparison between this standard and ASTM D5917-02 in clause/subclause number
