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D5917-24 – Standard Test Method Technical Guide
⚙️ Method Overview and External Calibration Principles
ASTM D5917-24 specifies a gas chromatographic (GC) method for determining total nonaromatic hydrocarbons and trace monocyclic aromatic hydrocarbons in toluene, mixed xylenes, and p-xylene. The purity of the primary aromatic product is calculated using the external standard calibration technique. Total aliphatic hydrocarbons (C1–C10) are detected from 0.001 mass % to 2.500 mass %. Individual monocyclic aromatic impurities (C6–C10) are detected from 0.001 mass % to 1.000 mass %. All measured values are expressed in SI units.
⚠️ Important Measurement Note: Per Section 1.2.1, a small amount of benzene in mixed xylenes or p-xylene may not be chromatographically distinguished from nonaromatic hydrocarbons. In this case, the concentration is determined and reported as a composite value. Refer to Section 6.1 of the standard for the specific calculation.
📊 Validated Impurity Detection Ranges
The method is validated for precise quantitation within specific concentration windows. Results must be rounded in accordance with Practice E29 to determine conformance with applicable product specifications.
| 🟦 Impurity Category | 📏 Carbon Range | 🎯 Measured Components | ⚡ Concentration Range (mass %) |
|---|---|---|---|
| Nonaromatic (Aliphatic) Hydrocarbons | C1 – C10 | Methane through Decanes | 0.001 to 2.500 |
| Monocyclic Aromatic Hydrocarbons | C6 – C10 | Benzene through C10 Aromatics | 0.001 to 1.000 |
🧪 Procedure Requirements and Referenced Practices
Execution of this test method relies on several companion ASTM standards. Fused silica capillary columns must be installed per Practice E1510. Liquid samples are handled per Practice D3437, and analytical calibration blends are prepared following Practice D4307. Quality control and assurance provisions should adhere to the guidelines in Guide D6809.
✅ Safety and Compliance: This standard does not purport to address all safety concerns. Users are responsible for establishing appropriate safety, health, and environmental practices. Specific hazard statements applicable to this test method are detailed in Section 9 of the full standard.
❓ Frequently Asked Questions
🔍 What is the primary scope of ASTM D5917-24?
This standard specifies a GC method using external calibration for determining total nonaromatic hydrocarbons and trace monocyclic aromatic hydrocarbons in toluene, mixed xylenes, and p-xylene. The purity of the target aromatic hydrocarbon is also calculated from the impurity data.
💡 What are the validated detection concentration ranges?
Total aliphatic hydrocarbons (C1–C10) can be detected from 0.001 mass % to 2.500 mass %. Individual monocyclic aromatic hydrocarbons (C6–C10) are detected from 0.001 mass % to 1.000 mass %.
⚡ How does this method differ from ASTM D7504?
ASTM D5917 quantifies impurities using an external standard calibration technique. In contrast, ASTM D7504 quantifies impurities using the effective carbon number method. Both target trace impurities in monocyclic aromatic hydrocarbons but use different calibration philosophies.
📌 How are benzene results reported when testing mixed xylenes?
According to Section 1.2.1, benzene may co-elute with nonaromatic hydrocarbons in mixed xylenes or p-xylene. In this instance, the benzene concentration is determined and reported as a composite value alongside the total nonaromatic content, as detailed in Section 6.1.