ASTM D4053 Test Method for Benzene in Motor and Aviation Gasoline by Infrared Spectroscopy
7. Apparatus
7.1 Absorption Cell, sealed. Windows of potassium bromide or other material having sufficient transmittance out to 440 cm(-1)(22.73 µm), in a cell having TFE-fluorocarbon plugs and nominal path length of 0.025 mm known to three significant numbers.

7.2 Clear Reference Block - A block made from the same material as cell windows for use in the reference beam path of a double-beam spectrometer.

7.3 Infrared Spectrometer, double-beam or single-beam, suitable for recording accurate measurements between 690 cm(-1)(14.49 µm) and 440 cm(-1) (22.73 µm). Refer to Practices E 932 and E 1421.

NOTE 1 - Absorbances for the bands specified in this test method are expected to fall within the linear operating range of modern spectrometers for the concentration range as defined.

8. Reagents
8.1 Benzene, spectroscopic or research grade. (Warning - Poison, carcinogen, harmful, or fatal if swallowed. Extremely flammable.)

8.2 Toluene, spectroscopic or research grade. (Warning - Flammable, harmful if inhaled.)

8.3 Isooctane (2,2,4-trimethylpentane) or n-Heptane, spectroscopic or research grade. (Warning - Isooctane and n-Heptane are extremely flammable, harmful if inhaled.)