6. Apparatus
6.1 Apparatus of the type shown in Fig.1 or Fig.2 is suitable for use with up to 50-mL samples of oil and consists of the following components:

NOTE 2 - This sample size has been found to be sufficient for most oils. However, oil that has had only limited exposure to air may contain much smaller amounts of nitrogen and oxygen. For these oils it may be desirable to increase the size of the sample and the extraction apparatus.

NOTE 3 - Alternative apparatus designs including the use of a Toepler pump have also been found successful.

6.1.1 Polytetrafluoroethylene (PTFE) Tubing, narrow-bore, terminated with a Luer-Lock fitted glass syringe, and leading to a solid plug, three-way, high-vacuum stopcock.

6.1.2 Degassing Flask, with a glass inlet tube, of sufficient volume to contain up to 50 mL of oil below the inlet tube, capable of being evacuated through a vacuum pump, containing a PTFE-coated magnetic spin bar, and mounted on a magnetic stirrer.

6.1.3 Means of Measuring Absolute Pressure within the apparatus.

6.1.4 Vacuum Pumping System, capable of evacuating the glassware to an absolute pressure of 13 10/-3 torr (130 mPa) or lower.

6.1.5 Vacuum Glassware, sufficiently large compared to the volume of the oil sample, so that virtually complete degassing is obtained and that the volumetric collection ratio is as large as possible. A 500-mL gas collecting flask has been found suitable.

6.1.6 High-Vacuum Valves or Stopcocks, employing the minimum necessary amounts of high-vacuum stopcock grease are used throughout the apparatus.

6.1.7 Gas Collection Tube, calibrated in 0.01-mL divisions, capable of containing up to 5 mL of gas, terminated with a silicone rubber retaining septum. A suitable arrangement is shown in Fig.3.

6.1.8 Reservoir of Mercury, sufficient to fill the collection flask and collection tube. (Warning - Mercury vapor is extremely toxic. Appropriate precautions should be taken.)