ASTM D3257 Methods for Aromatics in Mineral Spirits by Gas Chromatography
3. Summary of Test Methods
3.1 The material, with an internal standard, is introduced into a gas chromatographic column containing a strongly polar liquid phase. The polar phase has very little affinity for saturated and olefinic hydrocarbons while exhibiting a pronounced retention of aromatics. This selectivity, which is illustrated in Fig. 1, results in the elution of all saturated and olefinic hydrocarbons in the products described above prior to the elution of toluene. Either a thermal conductivity or flame ionization detector may be used. Calibration is obtained in Test Method A and C from a synthetic blend of the most important aromatic compounds. Internal standards are used in all three test methods. Typical chromatograms are shown in Fig. 2 and Fig. 3.
NOTE 1 - Refer to Practice E 260 for additional information on gas chromatography techniques.
4. Significance and Use
4.1 These test methods were developed to measure the types and amounts of aromatics in mineral spirits to determine compliance with air pollution regulations that restrict the aromatic content of solvents. They have been demonstrated to be workable and to produce accurate results. However, due to the sensitivity of the tests to operating variables, some laboratories having limited experience with gas chromatographic analyses of hydrocarbons may experience difficulty in performing the tests.
