ASTM D5442 Test Method for Analysis of Petroleum Waxes by Gas Chromatography
1. Scope
1.1 This test method covers the quantitative determination of the carbon number distribution of petroleum waxes in the range from n-C17 through n-C44 by gas chromatography using internal standardization. In addition, the content of normal and non-normal hydrocarbons for each carbon number is also determined. Material with a carbon number above n-C44 is determined by its difference from 100 mass % and reported as C45+.
1.2 This test method is applicable to petroleum derived waxes, including blends of waxes. This test method is not applicable to oxygenated waxes, such as synthetic polyethylene glycols (for example, Carbowax), or natural products such as beeswax or carnauba.
1.3 This test method is not directly applicable to waxes with oil content greater than 10 % as determined by Test Method D721.
1.4 The values stated in SI units are to be regarded as the standard.
1.5 This standard 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 consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D721 Test Method for Oil Content of Petroleum Waxes
D4307 Practice for Preparation of Liquid Blends for Use as Analytical Standards
D4419 Test Method for Determination of Transition Temperatures of Petroleum Waxes by Differential Scanning Calorimetry (DSC)
D4626 Practice for Calculation of Gas Chromatographic Response Factors
E260 Practice for Packed Column Gas Chromatography
E355 Practice for Gas Chromatography Terms and Relationships
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 carbon number - a number corresponding to the number of carbon atoms in a hydrocarbon.
3.1.2 cool on-column injection - a sample introduction technique in gas chromatography where the sample is injected inside the front portion of a partition column at a temperature at or below the boiling point of the most volatile component in the sample.
3.1.3 low volume connector - a metal or glass union designed to connect two lengths of capillary tubing. Usually designed so that the tubing ends are joined with a minimum of either dead volume or overlap between them.
3.1.4 non(normal paraffin)hydrocarbon (NON) - all other hydrocarbon types excluding those hydrocarbons with carbon atoms in a single length. Includes aromatics, naphthenes, and branched hydrocarbon types.
3.1.5 normal paraffin - a saturated hydrocarbon which has all carbon atoms bonded in a single length, without branching or hydrocarbon rings.
3.1.6 wall coated open tube (WCOT) - a term used to specify capillary columns in which the stationary phase is coated on the interior surface of the glass or fused silica tube. Stationary phase may be cross-linked or bonded after coating.
