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D1821-95 – Standard Test Method Technical Guide
📐 Test Method Summary and Scope
This test method, designated D 1821-95, covers the determination of inorganic chloride ions in askarels over the range of 0.02 to 100 ppm. The method employs potentiometric titration in an essentially nonaqueous medium to quantify chloride content.
Users are advised to follow all safety protocols, with specific precautions outlined in Section 8.2 of the standard.
⚙️ Apparatus and Electrode Configuration
The primary apparatus includes an electrometric titrimeter and a suitable electrode system. The most recommended system is a silver-glass combination due to its longevity and ease of maintenance. Alternative systems include silver-silver chloride and silver-mercurous sulfate electrodes, the latter requiring occasional repacking when the mercurous sulfate discolors.
| 🟦 Electrode Type | 📏 Description | ⚡ Maintenance Notes |
|---|---|---|
| Silver-Glass | Preferred system for long life | Minimal maintenance required |
| Silver-Silver Chloride | Satisfactory alternative | Standard care |
| Silver-Mercurous Sulfate | Contains Hg2SO4, limited lifespan | Repack when turns brown |
📊 Significance of Chloride Testing
Chloride ions in askarels can ionize in the presence of water, leading to corrosive conditions that may damage electrical apparatus. Since many askarels contain polychlorinated biphenyls (PCBs), which are federally regulated since 1978, compliance with handling and disposal regulations is mandatory.
Other halogens may interfere with this test, though they are rarely encountered in practice.
⚠️ Important: The presence of PCBs in askarels imposes regulatory obligations. Users must adhere to applicable Federal, state, and local regulations regarding continued use, handling, and disposal.
💡 Tip: Always use reagent grade water that is chloride-free as specified in Specification D 1193 to prevent contamination and ensure accurate titration results.
❓ Frequently Asked Questions
🔍 What concentration range does this method cover?
The test method is applicable for detecting inorganic chloride ions in askarels from 0.02 to 100 ppm.
💡 Why is chloride testing crucial for askarels?
Chlorides can ionize in water, causing corrosion that shortens the lifespan of electrical equipment containing askarels.
⚡ What are common interferences in this test?
Other halogens may interfere, but they are not normally present in askarel samples.
📌 What electrode system is recommended for best results?
The silver-glass electrode system is preferred due to its long life and easy maintenance, as specified in the standard.