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D5765-16 – Standard Test Method Technical Guide
ASTM D5765-16 establishes a standardized practice for the solvent extraction of total petroleum hydrocarbons (TPH) from soils and sediments using closed vessel microwave heating. This practice is designed to prepare samples for analytical methods such as gravimetry or gas chromatography, ensuring consistency and reliability in environmental testing. The standard specifies that values in SI units are standard, except for pressure units where inch-pound values are standard.
⚙️ Practice Overview and Scope
This practice is applicable to solid samples that can pass through a ten mesh screen (approximately 2 mm openings). The solvent extract obtained can be analyzed for total or specific nonvolatile and semivolatile petroleum hydrocarbons. However, sample clean-up procedures may be necessary for specific compound analysis. This practice is limited to solvents recommended for use in microwave solvent extraction systems, ensuring safety and efficacy. The significance and use of this practice include providing information on the availability of petroleum hydrocarbons to leaching, water quality changes, and other site conditions.
🔬 Extraction Procedure and Parameters
The chemical portion of this practice involves solvent extraction to dissociate petroleum hydrocarbons from the matrix. Specifically, the sample is extracted with acetone/hexane in a sealed microwave transparent vessel. Microwave heating is used to achieve an internal temperature of 150°C, which is critical for effective extraction. The sealed vessel minimizes loss of volatile components and ensures safety. The resulting extract is suitable for analysis by gas chromatography or gravimetric measurements.
| 🟦 Parameter | 📏 Specification | 🎯 Details |
|---|---|---|
| Solvent System | Acetone/Hexane | Recommended for microwave extraction |
| Extraction Temperature | 150°C | Internal temperature of vessel |
| Sample Preparation | Pass through 10 mesh | Approximately 2 mm openings |
| Analytical Methods | Gravimetric or GC | For petroleum hydrocarbon determination |
📏 Key Specifications and Standards
This standard references several ASTM standards and federal regulations to ensure consistency and safety in testing. These references provide additional guidance on terminology, sample preparation, and laboratory practices.
| 🟦 Standard | 📘 Description |
|---|---|
| D1129 | Terminology Relating to Water |
| D3694 | Practices for Sample Container Preparation |
| D3976 | Preparation of Sediment Samples for Chemical Analysis |
| D5368 (Withdrawn) | Gravimetric Determination of Total Solvent Extractable Content |
| CFR Title 21 & 47 | Federal Standards for Microwave Radiation Safety |
⚠️ Safety Note: Users must establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 9 of the standard. This includes adherence to CFR Title 21 and 47 regarding microwave radiation.
💡 Technical Tip: The solvent extract may require sample clean-up procedures prior to specific compound analysis, especially for semivolatile or nonvolatile hydrocarbons. Refer to Practices D3694 for sample container preparation to avoid contamination. Additionally, ensure that the microwave vessel is compatible with the solvent system used.
❓ Frequently Asked Questions
🔍 What is the scope of ASTM D5765-16?
The practice covers solvent extraction of total petroleum hydrocarbons from soils and sediments using closed vessel microwave heating for subsequent determination by gravimetric or gas chromatographic techniques.
💡 Which solvents are recommended for extraction?
The recommended solvent system is acetone/hexane, as specified in the standard. This solvent combination is optimized for microwave extraction efficiency.
⚡ What extraction temperature is required?
The microwave heating is used to achieve an internal temperature of 150°C in the sealed vessel. This temperature is critical for dissociating petroleum hydrocarbons from the soil or sediment matrix.
📌 What sample preparation is needed before extraction?
Samples must be solid and pass through a ten mesh screen (approximately 2 mm openings). This ensures uniformity and proper contact with the solvent during extraction.