ASTM D4768 for 2,6-Ditertiary-Butyl Para-Cresol and 2,6-Ditertiary-Butyl Phenol
ASTM D4768 Standard Test Method for Analysis of 2,6-Ditertiary-Butyl Para-Cresol and 2,6-Ditertiary-Butyl Phenol in Insulating Liquids by Gas Chromatography
5. Apparatus
5.1 Gas Chromatograph, equipped with oven temperature control constant to 1°C and with heated injector port.
5.1.1 Means to Record the Chromatogram, such as a pen recorder or a digital integrator to determine peak areas, is recommended. An automated sample injector may be used.

5.2 Flame Ionization Detector, with appropriate hydrogen/air gas flows, is preferred over a thermal conductivity detector to provide maximum sensitivity.

5.3 Column, a suitable stainless steel or glass column packed with a nonpolar silicone on an appropriate support or equivalent capillary column.

NOTE 1 - A 3 % OV-1 on 100/120 Mesh Supelcoport, 1.83 m (6 ft) long, 3.2 mm (0.125 in.) in outside diameter has been used successfully. A SPB-1 30 m by 0.53 mm 1µm film column has also been used successfully.

5.3.1 Condition columns in accordance with manufacturer's recommendations. Disconnect columns from detector prior to conditioning and reconnect after conditioning.

5.4 Precision Syringe, glass, 10.0 µL.

5.5 Volumetric Glassware, appropriate for making dilutions.

5.6 Pipets, Pasteur, disposable, 146 by 7.5 mm.

5.7 Analytical Balance.

5.8 Automatic Pipetter, 1 mL calibrated, adjustable.

5.9 Oven, capable of maintaining a temperature of 325 ± 5°C for conditioning extraction columns.

5.10 Desiccator.

6. Reagents and Materials
6.1 Purity of Reagents - Use reagent grade chemicals 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 sufficient purity to permit its use without lessening the accuracy of the determination.

6.2 2,6-ditertiary-butyl phenol (DBP).

6.3 2,6-ditertiary-butyl para-cresol (DBPC-) - Also known as butylated hydroxytoluene (BHT).

6.4 Glass Wool.

6.5 Aluminum Oxide (Alumina), acid powder, ACS, Brockman Activity Grade 1, for chromatography.

6.6 Hexane or Heptane, ACS reagent grade.

6.7 Methanol, anhydrous, ACS reagent grade.

6.8 Mineral Oil, inhibitor-free, transformer grade.