ASTM D7423-17 pdf download.Standard Test Method for Determination of Oxygenates in C2, C3, C4, and C5 Hydrocarbon Matrices by Gas Chromatography and Flame Ionization Detection.
3. Terminology
3.1 Additional terminology related to the practice of gas chromatography can be found in Practice E355.
3.2 Definitions:
3.2.1 liquefied petroleum gas (LPG), n—a mixture of nor- mally gaseous hydrocarbons, predominantly propane or butane, or both, that has been liquefied by compression or cooling, or both, to facilitate storage, transport, and handling. D4175 3.2.2 oxygenate, n—an oxygen-containing ashless organic compound, such as an alcohol or ether, which may be used as a fuel or fuel supplement. D4175 3.3 Definitions ofTerms Specific to This Standard:
3.3.1 Dean’s switching method—representative aliquot of sample is injected on-column using a sample valve (or via a gas chromatograph split inlet). The sample passes onto a nonpolar column, which elutes the lighter hydrocarbons in boiling point order to the analytical column and backflushes the heavier hydrocarbons to vent. The oxygenate compounds elute from the analytical column and are detected via a flame ionization detector.
3.3.2 Dean’s switching method direct inject—gas chromato- graphic valve configuration equipped with a valve connected directly to the precolumn. This technique is commonly used for the determination of oxygenates in ethene and propene con- centrates. This configuration provides the lowest detection limits such as those commonly required for ethene and propene concentrates.
3.3.3 Dean’s switching method equipped with a split inlet— gas chromatographic valve configuration equipped with a gas chromatograph split inlet for sample introduction into the precolumn. This configuration is commonly used for the determination of oxygenates in C5 hydrocarbon mixtures. This technique using this configuration might not provide the detection limits noted in the scope of this test method. If lower detection limits are required, then the user should consider using the on-column valve direct injection technique.
3.3.4 valve cut method—commonly used for the determina- tion ofoxygenates in C4 hydrocarbon mixtures. This technique using a split inlet might not provide the detection limits noted in the scope of this test method. If lower detection limits are required, then the user should consider using the on-column valve direct injection technique.
3.3.5 valve cut method equipped with a split inlet— representative aliquot of sample is injected via a gas chromato- graph split inlet for sample introduction into the precolumn. The sample passes onto a nonpolar column, which elutes the lighter hydrocarbons in boiling point order to the analytical column and the heavier hydrocarbons to vent. The oxygenate compounds elute from the analytical column and are detected via a flame ionization detector.
3.4 Acronyms:
3.4.1 DIPE—diisopropylether.
3.4.2 ETBE—ethyl tert-butylether.
3.4.3 MEK—2-butanone.
3.4.4 MTBE—methyl tert-butylether.
3.4.5 TAME—tert-amyl methylether.
3.4.6 PLOT—porous layer open tubular capillary column.
3.4.7 WCOT—wall coated open tubular capillary column.ASTM D7423 pdf download.