7. Apparatus
7.1 Gas Chromatograph - Instrumentation capable of operating at the conditions listed in Table 1. A heated flash vaporizing injector designed to provide a linear sample split injection (that is, 200:1) is required for proper sample introduction. Carrier gas controls must be of adequate precision to provide reproducible column flows and split ratios in order to maintain analytical integrity. Pressure control devices and gauges must be designed to attain the linear velocity required in the column used (for example, if a 150 m column is used, a pressure of approximately 550 kPa (80 psig) is required). A hydrogen flame ionization detector with associated gas controls and electronics, designed for optimum response with open tubular columns, is required.
7.2 Sample Introduction - Manual or automatic liquid syringe sample injection to the splitting injector is employed. Devices capable of 0.1 µL to 0.5 µL injections are suitable. It should be noted that inadequate splitter design, or poor injection technique, or both can result in poor resolution. Overloading of the column can also cause loss of resolution for some components and, since overloaded peaks are skewed, variation in retention times. Watch for any skewed peaks that indicate overloading during column evaluation. Observe the component size and where possible, avoid conditions leading to this problem during the analyses.
7.3 Open Tubular Column - This test method utilizes a fused silica open tubular column with non-polar methyl silicone bonded (cross-linked) phase internal coating such as one of the following:
Other columns with equal or greater resolving power may be used. A minimum resolution between trans-2-pentene and tert-butanol, and between cis-2-pentene and tert-butanol of 1.3 is required. The 150 m column is expected to decrease the likelihood of co-elution of impurities.
7.4 Electronic Data Acquisition System - Any data acquisition and integration device used for quantification of these analyses must meet or exceed these minimum requirements:
7.4.1 Capacity for at least 50 peaks per analysis,
7.4.2 Normalized area percent calculations with response factors,
7.4.3 Identification of individual components based on retention time,
7.4.4 Noise and spike rejection capability,
7.4.5 Sampling rate for fast (<1 s) peaks,
7.4.6 Positive and negative sloping baseline correction,
7.4.7 Peak detection sensitivity compensation for narrow and broad peaks, and
7.4.8 Non-resolved peaks separated by perpendicular drop or tangential skimming as needed.
8. Reagents and Materials
8.1 Carrier Gas, helium, 99.99 % pure. (Warning - Compressed gas under high pressure.)
8.2 Fuel Gas, hydrogen, 99.99 % pure. (Warning - Extremely flammable gas under pressure.)
8.3 Oxidant, air, oil free. (Warning - Compressed gas under high pressure.)
8.4 Make-Up Gas, nitrogen, 99.99 % pure. (Warning - Compressed gas under high pressure.)
8.5 Reference Standards:
8.5.1 tert-Amyl methyl ether, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.2 Butane, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.3 tert-Butanol, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.4 sec-Butyl methyl ether, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.5 4,4-Dimethyl-2-neopentyl-1-pentene, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.6 Isobutylene, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.7 Methanol, (Warning - See Note 1.)
NOTE 1 - Warning: Toxic Flammable Liquid. Harmful if inhaled or ingested.
8.5.8 2-Methyl-2-butene, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.9 Methyl tert-butyl ether, 99 + % pure, 8,5 (Warning - Flammable liquid. Harmful if inhaled.)
8.5.10 2,2,4,6,6-Pentamethyl-3-heptene, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.11 n-Pentane, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.12 cis-2-Pentene, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.13 trans-2-Pentene, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.14 2,4,4-Trimethyl-1-pentene, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.15 2,4,4-Trimethyl-2-pentene, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.16 1 % Contaminant Standard, contains 1.0 % of some of the contaminants in MTBE, (Warning - Flammable liquid. Harmful if inhaled.)
8.5.17 0.1 % Contaminant Standard, contains 0.1 % of some of the contaminants in MTBE, (Warning - Flammable liquid. Harmful if inhaled.)