ASTM D3634 Standard Test Method for Trace Chloride Ion in Engine Coolants
5. Apparatus
5.1 Manual Titrations:
5.1.1 pH Meter - An expanded scale pH meter which can be read to 1 or 2 mV is desirable but not required. A silver billet indicator electrode and glass reference electrode are used for the chloride titration. The silver electrode should be polished occasionally with fine steel wool or scouring powder and thoroughly rinsed.
5.1.2 Buret, 10-mL, micro, Class A, calibrated in 0.02-mL divisions.
5.1.3 Beakers, electrolytic, 250-mL tall form.
5.2 Automatic Titrators are satisfactory for this test method, provided they exhibit resolution and accuracy equivalent to that specified for manual titrations.
5.3 Pipets, 10, 20, and 100-mL, Class A.
5.4 Flask, Erlenmeyer, 250 mL, with a 24/40 standard taper, female ground glass joint.
5.5 Condenser - The condenser shall be of the water-cooled, reflux, glass-tube type, having a condenser jacket approximately 200 mm in length. The bottom end of the condenser shall have a 24/40 male ground glass joint to match the Erlenmeyer flask.
5.6 Flask, volumetric, 200 mL, Class A.
NOTE 1 - All glassware should be thoroughly cleaned and reserved for use in this test method. Great care must be exercised to avoid contamination. Glassware should be cleaned with chromic acid (Warning - See 7.1.) cleaning solution, then thoroughly rinsed with water, then with acetone (Warning - See 7.2.), and dried.
6. Reagents and Materials
6.1 Purity of Reagents - Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use without lessening the accuracy of the determination.
6.2 Purity of Water - References to water shall be understood to mean Type IV reagent water conforming to Specification D1193: total particulate and dissolved matter, 2.0 mg/L maximum; pH at 25°C, 5.0 to 8.0; electrical conductivity at 25°C, 5.0 µmho/cm maximum; minimum color retention time of potassium permanganate, 10 min.
6.3 Acetic Acid, Glacial (Warning - See 7.3.).
6.4 Hydrogen Peroxide Solution - (Warning - See 7.4.) Use 30 mass % hydrogen peroxide (H2O2), reagent grade. Aged or contaminated H2O2 can undergo considerable decomposition and cause incomplete oxidation of the sulfur compounds with subsequent high apparent chloride values; therefore, fresh reagent should be used.
6.5 Potassium Chloride Solution - Dissolve 0.20 +/- 0.02 g of potassium chloride (KCl) in 100 mL of water. The solution will contain 1 mg of chloride per mL solution.
6.6 Silver Nitrate Solution - (Warning - See 7.5.) Prepare a standard 0.01 N silver nitrate (AgNO3) solution weekly by diluting 10 mL of standard 0.1 N aqueous AgNO3 solution to 100 mL with water. The 0.1 N standard AgNO3 solution should be prepared and standardized in accordance with Sections 44 to 48 of Practice E200.
6.7 Sodium Hydroxide Solution - (Warning - See 7.6.) Prepare a 20 mass % sodium hydroxide (NaOH) solution in water.
