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D2427-06 – Standard Test Method Technical Guide
🧪 Scope and Analytic Target
ASTM D2427-06 (Reapproved 2019) provides a standardized gas chromatography method for determining C2 through C5 paraffins and mono-olefins in gasolines. It is essential for characterizing the light hydrocarbon fraction, directly influencing fuel volatility and vapor pressure. The standard covers sixteen specific components, including ethane/ethylene, propane, butane isomers, and pentene isomers, explicitly excluding cyclic olefins, diolefins, or acetylenes. Samples must not contain significant material boiling lower than ethylene.
🪁 Depentanization Note: Highly volatile fuels may require stabilization by depentanization (Test Method D2001) prior to analysis to avoid light-end losses.
⚙️ Test Procedure and Quantification
The sample is injected into a gas-liquid partition column with an inert carrier gas. Components are separated and detected as a chromatogram. C6+ materials can be backflushed or regrouped into a single peak by reversing carrier gas flow. Quantification is achieved by adding a low-boiling internal standard, or by comparing peak areas of a known sample mass against a standard sample run under identical conditions. Calibration is performed using known amounts of calibration standards or a synthetic blend.
📊 Reported Components and Standard Data
Concentrations are reported by volume or mass (weight) for C2 through C5 hydrocarbons. SI units are standard, with alternative units provided for clarity.
| 🟦 Carbon Group | 📏 Reported Analytes |
|---|---|
| C2 | Ethylene plus Ethane |
| C3 | Propane, Propylene |
| C4 | Isobutane, n-Butane, Butene-1 plus Isobutylene, trans-Butene-2, cis-Butene-2 |
| C5 | Isopentane, 3-Methylbutene-1, n-Pentane, Pentene-1, 2-Methylbutene-1, trans-Pentene-2, cis-Pentene-2, 2-Methylbutene-2 |
The method is under the jurisdiction of ASTM Subcommittee D02.04.0L. The current edition was approved in 2019, with its original approval in 1965.
| 🆔 Designation Detail | 📅 Value |
|---|---|
| Full Designation | D2427 −06 (Reapproved 2019) |
| Originally Approved | 1965 |
| Last Reapproval Year | 2019 |
⚠️ Limitation: This test method does not cover cyclic olefins, diolefins, or acetylenes. Users must ensure the sample matrix is within this scope. The standard does not purport to address all safety concerns.
❓ Frequently Asked Questions
🔍 What is the scope of ASTM D2427?
The test method covers the determination of C2 through C5 paraffins and mono-olefins in gasolines by gas chromatography, listing sixteen specific analytes.
💡 How are C6 and heavier components handled?
Materials with more than five carbon atoms are either backflushed from the system without measurement or recorded as a broad peak by reversing the carrier gas flow.
⚡ What quantification methods are specified?
Quantification involves adding a low-boiling internal standard or comparing a known sample mass to a standard sample. Peak areas are compared to calibration standards.
📌 Does the standard include deep boiling point cuts?
Samples should not contain significant amounts of material boiling lower than ethylene to ensure the integrity of the separation and quantification.