ASTM D5917 Test Method for Trace Impurities in Monocyclic Aromatic Hydrocarbons
ASTM D5917 Standard Test Method for Trace Impurities in Monocyclic Aromatic Hydrocarbons by Gas Chromatography and External Calibration
7. Apparatus
7.1 Gas Chromatograph - Any instrument having a flame ionization detector that can be operated at the conditions given in Table 1. The system shall have sufficient sensitivity to obtain a minimum peak height response for 0.001 weight % impurity of twice the height of the background noise.
7.2 Columns - The choice of column is based on resolution requirements. Any column may be used that is capable of resolving all significant impurities from the major component. The column and conditions described in Table 1 have been used successfully and shall be used as a referee in cases of dispute.
7.3 Recorder - Electronic integration is recommended.
7.4 Injector - The specimen must be precisely and repeatably injected into the gas chromatograph. An automatic sample injection device is highly recommended although manual injection can be employed if the criteria in 12.7 can be satisfied.
7.5 Volumetric Flask, 100-mL capacity.
7.6 Syringe, 100 µL.
8. Reagents
8.1 Purity of Reagent - Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available.
8.2 Carrier Gas - Chromatographic grade helium or hydrogen, 99.999 % is recommended. Purify carrier, makeup and detector gases to remove oxygen, water, and hydrocarbons.
8.3 Air, Chromatographic grade, containing less than 0.1 ppm THC.
8.4 High Purity p-Xylene, 99.999 weight % or greater purity.
8.4.1 Most p-xylene is available commercially at a purity less than 99.9 % and can be purified by recrystallization. To prepare 1.9 L of high purity p-xylene, begin with approximately 3.8 L of material and cool in a flammable storage freezer at -10 ± 5°C until approximately 1/2 to 3/4 of the p-xylene has frozen. This should require about 5 h. Remove the sample and decant the liquid portion. The solid portion is the purified p-xylene. Allow the p-xylene to thaw and repeat the crystallization procedure on the remaining sample until the p-xylene is free of contamination as indicated by gas chromatography.
8.5 Pure compounds for calibration, shall include n-nonane, benzene, toluene, ethylbenzene, o-xylene, m-xylene, and cumene. If applicable, the calibration may include paradiethylbenzene (PDEB). The purity of all reagents should be >99 weight %. If the purity is less than 99 %, the concentration and identification of impurities must be known so that the composition of the standard can be adjusted for the presence of the impurities.
9. Hazards
9.1 Consult current OSHA regulations, supplier's Material Safety Data Sheets, and local regulations for all materials used in this test method.
10. Sampling
10.1 Sample the material in accordance with Practice D3437.
11. Preparation of Apparatus
11.1 Follow manufacturer's instructions for mounting and conditioning the column into the chromatograph and adjusting the instrument to the conditions described in Table 1, allowing sufficient time for the equipment to reach equilibrium. See Practices E260, E355, and E1510 for additional information on gas chromatography practices and terminology.
